Chapter 4

This is the html version of the file http://veterans.senate.gov/Reports/chapt4.pdf.
G o o g l e automatically generates html versions of documents as we crawl the web.

Google is neither affiliated with the authors of this page nor responsible for its content.

Page 1

157

POSSIBLE LONG TERM HEALTH

CONSEQUENCES OF GULF WAR EXPOSURES:

AN INDEPENDENT EVALUATION

INTRODUCTION

his chapter provides an independent examination of the long-term health consequences of Gulf

War exposures by nationally recognized scientific experts. Chapter Three reviewed many of the

complexities associated with the question of “Why are Gulf War veterans ill?” as well as some of the

reasons why this question may never be answered. In an effort to examine what is known regarding

the health effects of some of the exposures experienced by troops during the Gulf War, the SIU

contracted with the following scientists.

This chapter contains the brief reports prepared by the consultants listed below. (The

consultants’ affiliations are provided for identification purposes only.) They are, in the order their

reports appear in this chapter:

FredricGerr, M.D., Peachtree Environmental Consultants Inc., Decatur, Georgia; and Associate

Professor, Department of Environmental and Occupational Health, Rollins School of Public Health

of Emory University, Atlanta, Georgia. Dr. Gerr examined the chemicals that were in the Gulf, such

as solvents, pesticides, depleted uranium, and others, for their potential health effects particularly

upon the brain and nervous system. (Dr. Gerr’s detailed report is at Appendix II.)

MatthewKeifer, M.D., M.P.H., Assistant Professor, Occupational and Environmental Medicine

Program, Departments of Medicine and Environmental Health, Harborview Medical Center,

Universityof Seattle, Washington. Dr. Keifer examined the total range of health effects to exposures

to pesticides and related chemicals such as pyridostigmine bromide and some chemical nerve agents

that are similar to pesticides. (Dr. Keifer’s detailed report is at Appendix JJ.)

James Moss, Ph.D., Gainesville, Florida. Dr. Moss looked at the use of PB as it acts with

combinations of other agents such as certain pesticides.

Richard Letz, Ph.D., Peachtree Environmental Consultants Inc., Decatur, Georgia; and Associate

Professor,Department of Behavioral Sciences and Health Education, Rollins School of Public Health

Page 2

United States Senate Committee on Veterans’ Affairs

158

of Emory University, Atlanta, Georgia. Dr. Letz evaluated the health effects of stress as an

occupational and or environmental exposure in the Gulf.

Michael Lebowitz, Ph.D., Professor of Medicine, Pulmonary and Critical Care Medicine;

Professor and Director of Epidemiology, Arizona Prevention Center; Chair, Epidemiology Graduate

Interdisciplinary Program, University of Arizona, Tucson. Dr. Lebowitz examined the long-term

health effects of sources of indoor and outdoor air pollutants during the Gulf War including oil well

fires, sand, space heaters used in unvented tents, and other sources. (Dr. Lebowitz’s detailed report

is at Appendix KK.)

Kevin Dybvig, Ph.D., Professor, Departments of Comparative Medicine and Microbiology,

University of Alabama at Birmingham. Dr. Dybvig evaluated the potential role of infection with

Mycoplasma fermantans in the health problems of Gulf War veterans.

Shanna Swan, Ph.D., Chief, Reproductive Epidemiology Section, California Department of

HealthServices. Dr. Swan evaluated reproductive health issues from an epidemiological perspective.

(Dr. Swan’s detailed report is at Appendix LL.)

Melissa McDiarmid, M.D., M.P.H., Associate Professor of Medicine, Occupational Health

Project, University of Maryland; and Director, Depleted Uranium Follow-up Program, Baltimore

Veterans’ Affairs Medical Center. Dr. McDiarmid examined the chemicals that were in the Gulf,

suchas solvents, pesticides, and depleted uranium, for their potential to adversely affect reproductive

health outcomes. Dr. McDiarmid also examined the chemicals associated with the Gulf War

deployment for their potential to increase the risk of cancer among Gulf War veterans. (Dr.

McDiarmid’s detailed reports are at Appendix MM and NN.)

Page 3

Report of the Special Investigation Unit on Gulf War Illnesses

159

HEALTH EFFECTS OF EXPOSURES TO NEUROTOXIC

AGENTS USED IN THE PERSIAN GULF WAR

Prepared by: Fredric Gerr, M.D., Peachtree Environmental Consultants, Inc., Decatur,

Georgia; and Department of Environmental and Occupational Health, Rollins School of Public

Health of Emory University, Atlanta, Georgia

SUMMARY

he purpose of this report is to review in detail the known health effects of chemical agents

potentially hazardous to the nervous system to which military personnel may have been exposed

during the Persian Gulf War. This review is made with special attention to possible relationships

between these agents and symptoms and health complaints that have been reported by a large

number of Persian Gulf War veterans.

OnAugust 2, 1990, Iraq invaded Kuwait and set in motion the events that would eventually lead

to US military intervention in the Persian Gulf. On August 8, 1990, the first US Air Force planes

arrived in Saudi Arabia and, on the following day, the first US ground forces arrived. The ground

war began and ended in February, 1991. The last of the US service members who served in the

ground war were returned to the United States in June, 1991.

In all, the United States had approximately 697,000 troops stationed in the Persian Gulf.

Following their return, mounting concern has focused on symptoms and unexplained illness

experienced by some. In response to concern about unexplained illness, the VA Persian Gulf Health

Registry was created. As of June, 1994, over 17,000 veterans, either ill or concerned about illness,

had enrolled. The ten most frequent complaints among those in the Registry were fatigue (17.4%),

rash (16.8%), headache (14.1%), muscle and or joint pain (13.9%), neuropsychologic complaints

(10.5%), shortness of breath (7.5%), sleep disturbances (4.9%), gastrointestinal disturbance (4.1%),

cough (3.8%), and other respiratory complaints (3.3%) (Persian Gulf Veterans Coordinating Board,

1995). The registry has not shed light on any distinctive demographic, exposure, or geographic risk

factor, with the possible exception that nearly half of the veterans with symptoms were

reservists/National Guard personnel, a group that accounted for only 17% of all troops deployed in

the Persian Gulf (Persian Gulf Veterans Coordinating Board, 1995).

Numerous possible risks to health were present in the Persian Gulf at the time of the Gulf War.

These included poor living conditions, characterized by heat and humidity, initially, and cold during

the actual combat. Troops slept in temporary housing with little personal privacy. Food consisted

Page 4

United States Senate Committee on Veterans’ Affairs

160

mainly of prepackaged meals. Flies and other insects were prevalent. Chemical warfare alarms

sounded frequently, although virtually all were false. Such alarms, nevertheless, resulted in donning

of air purifying masks and chemical protective clothing. Attention has been paid to possible

chemicalwarfare agent exposure in the Gulf occurring as a result of destruction of a chemical warfare

agent facility at Kamisiyah. Iraq was reported to have stockpiled biological warfare agents as well.

Concern about health effects from exposure to these weapons as well as to indigenous infectious

diseases lead to an extensive vaccination program. In addition, an estimated quarter of a million

troopstook the chemical warfare agent protective drug pyridostigmine bromide. Pesticides were used

to control insect populations and insect repellents were provided to troops for personal use. Some

troopswere exposed to solvents from jet fuel, paint vapors, and other sources. Depleted uranium was

usedin special applications during the Gulf War and tetra-ethyl lead was formulated in gasoline used

inmotor vehicles. Finally, some troops were exposed to non-ionizing radiation from microwaves and

radar installations (PAC, 1996).

In order to better characterize the health complaints of Gulf War veterans and to determine

whether exposure to hazardous substances in the Gulf had caused them, health investigations of

morbidity and mortality among Persian Gulf War veterans have been performed.

The largest and most methodologically sound study investigation included nearly five thousand

subjects and involved inquiry about symptoms and exposure to known hazards in the Persian Gulf

(Schwartzet al., 1997). Military personnel who served in the Persian Gulf War reported significantly

more symptoms of depression, PTSD, chronic fatigue, cognitive dysfunction, bronchitis and asthma

than non-Persian Gulf War personnel. Most of the self-reported exposures to hazards were

statistically significantly related to virtually all of the health outcomes studied.

The results of the study indicate that subjective symptoms, including those consistent with

nervous system impairment, occur more frequently among those who served in the Persian Gulf War

than Persian Gulf War-era personnel who were not stationed in the Persian Gulf. The associations

between multiple, unrelated exposures and multiple, unrelated symptoms, however, is more

consistent with differential recall of exposure as a function of symptoms experience than a toxic

response to a single or even several agents.

Several other studies intended to characterize with more objective measures the neurological

health of Gulf War Veterans have been published. Authors of some suggest that the results show

neither increased nervous system impairment nor a consistent pattern of illness suggestive of a

common etiology (Amato et al., 1997; Jamal et al, 1996). Conversely, others conclude that their

results show an increase in nervous system impairment and a pattern consistent with exposure to

specific neurotoxicants (Haley et al., 1997). Unfortunately, nearly all of these studies were

performed on “samples of convenience” and, as a result, cannot be used to draw conclusions about

the larger but unstudied group of all Gulf War veterans. This body of literature has added little to

the collective understanding of symptoms and health concerns among Persian Gulf War veterans.

Page 5

Report of the Special Investigation Unit on Gulf War Illnesses

161

Epidemiologic investigation of relationships between potentially toxic substances and ill health

require accurate and unbiased assessment, on an individual basis, of both health status and the

intensity and type of exposures experienced among a sample of persons representative of the entire

group at risk. Of these requirements, the task that appears nearly impossible at this time is a person

by person estimation of the intensity and type of exposures experienced by military personnel who

served during the Persian Gulf War. Characterization of exposure to hazards was, apparently, not

performed during the actual deployment of troops. As a result, estimation of the magnitude of past

hazardousexposure at this time requires either direct questioning of veterans with resulting reporting

bias or historical exposure reconstruction of unknown validity. As indicated above, reporting bias

likely accounts for the associations observed in one study between symptoms and a very wide range

of potential hazards.

As an alternative to epidemiologic investigation, another approach to investigating associations

betweenhealth and hazardous exposure is to focus separately on 1) health problems among veterans

and 2) exposures which they might have experienced. If a characteristic illness is observed among

GulfWar veterans, then known causes for it can be explored. If particular hazards were encountered

byveterans in the Gulf, the known health effects of exposure to them can be reviewed and compared

to reported health problems among veterans. As neither approach attempts to relate exposure to

illness on an individual basis, considerable caution must be exercised in their execution and

interpretation. This report employs the latter of these two approaches and provides a systematic

review of health effects of substances potentially toxic to the nervous system to which military

personnelmay have been exposed during the Persian Gulf War. A summary of the review is provided

below.

Pyridostigmine bromide is an anticholinesterase drug given to tens of thousands of military

personnel in the Persian Gulf war as a protective pre-treatment for exposure to “nerve gas” type

chemical warfare agents (Dirnhuber et al, 1979). It is a member of the carbamate class of chemical

agents and has been used for decades in humans as a treatment for the neurological disorder

Myasthenia Gravis as well as a short acting accelerator of recovery from certain anesthetic agents.

Pyridostigmine bromide acts by binding reversibly to, and consequently inhibiting, the enzyme

acetylcholinesterase, which is necessary for normal function of the nervous system. This action is

the basis for its ability to protect against the lethal effects of nerve agents which bind irreversibly to

this enzyme. Pyridostigmine bromide is known to cause short-term discomfort and its use in the Gulf

War was associated with abdominal distress, nausea, and diarrhea (Keeler et al., 1991; Sharabi et al.,

1991). Little epidemiologic information is available about its long-term effects healthy young human

populations,however, several factors suggest few or no long term effects on the nervous system. First,

it has been used for decades for treatment of neurological illness with no systematic occurrence of

symptoms resembling those experienced by Gulf War veterans. Second, the agent is not known to

pass through the natural barrier that protect the brain from many drugs and chemicals (the “blood

brain barrier”), thereby making effects on the brain unlikely. Third, the class of drugs and chemical

Page 6

United States Senate Committee on Veterans’ Affairs

162

agents to which Pyridostigmine belongs, carbamates, have been used extensively in agriculture for

decades and are not known to cause persistent adverse effects on the nervous system in that setting.

Chemical warfare agents, known as “nerve gas”, are members of the organophosphate class of

chemical compounds. The organophosphate nerve agents act to irreversibly bind the enzyme

acetylcholinesterase (Grob and Harvey, 1957). Accumulation of the intended substrate of

acetylcholinesterase, the neurotransmitter acetylcholine, results in a characteristic complex of

symptoms. Unlike pyridostigmine, which also binds the enzyme acetylcholinesterase (reversibly,

however), the organophosphate chemical warfare agents are capable of freely penetrating the brain

and producing acute and chronic central nervous system toxicity.

Most of what is known about the effects of chemical warfare agents is a result of experimental

studies of exposure to animals (Blick et al, 1994). However, several studies or case reports of acute

human effects of exposure were identified in the literature (Grob and Harvey, 1957; Sidell, 1974).

In addition, because of their chemical and toxicological similarity to organophosphate pesticides,

some inferences about their toxicity can be made from the considerable literature about the

organophosphate pesticides. Short term, acute exposure to chemical warfare agents produces a

characteristic array of symptoms including sweating, diarrhea, urination, muscle twitching, pinpoint

pupils, confusion, seizures, and, with sufficient exposure, death. Some credible medical evidence

suggests that, upon recovery from toxic effects of acute exposure, chronic impairment of the central

nervous system may occur (Sidell, 1974; Burchfiel and Duffy, 1982). Little evidence is available to

suggest that exposures insufficient to produce acute toxicity are associated with long term

neurological effects. Reportedly, no military personnel were treated for acute effects of nerve agent

exposure, making unlikely that chronic effects of such exposure are the cause of symptoms

experienced by Persian Gulf War veterans.

Organophosphate pesticides were used in the Persian Gulf for control of insects. Because of

widespread use of organophosphate pesticides worldwide, a larger body of literature about the acute

and chronic health effects of organophosphate pesticides on human populations, including chronic

effectson the CNS, is available than is available for organophosphate chemical warfare agent agents.

Inaddition to the organophosphate class of pesticides, carbamate, pyrethroid, and organochlorine

pesticides were also used. Only the organophosphate pesticides are known to cause, under certain

exposurecircumstances, long-term adverse effects on the nervous system. The carbamate pesticides,

although similar in acute toxicity to organophosphates, are not known to result in long-term adverse

neurological effects. Similarly, long-term adverse neurological effects of pyrethroid insecticides, and

Lindane, the one organochlorine pesticide used in the Persian Gulf, have not been reported in the

peer reviewed medical literature.

Exposure to organophosphate pesticides has been most convincingly associated with chronic

adverse central nervous system health effects only when the exposure intensity is sufficient to

Page 7

Report of the Special Investigation Unit on Gulf War Illnesses

163

produce acute toxicity consistent with acetylcholinesterase inhibition (Steenland et al, 1994; Ames

et al., 1995; Savage et al., 1988; Rosenstock et al., 1991). Only one report in the literature related

exposures to levels of organophosphate pesticides insufficient to produce acute effects to long-term

adverse effects on the central nervous system (Korsak and Sato, 1977). This finding has not been

duplicated by other investigators. Given the apparent absence of documented signs and symptoms

characteristic of acute organophosphate pesticide toxicity among soldiers deployed to the Persian

Gulf, it unlikely that long-term health effects of pesticide toxicity is responsible for symptoms

described by Persian Gulf veterans.

Lead, in the form of tetra-ethyl lead, was an octane boosting additive in gasoline used to fuel

motor vehicles used by US forces in the Persian Gulf. Tetra-ethyl lead had been used in gasoline in

theUnited States for decades and was widely discontinued from such use, for protection of the public

health,beginning in the 1970’s. Exposure to lead in the Persian Gulf War was limited to that emitted

from vehicles in which leaded gasoline was used.

Both organic and inorganic lead are known to be toxic to the nervous system. Clinically,

symptoms of lead intoxication include abdominal pain, fatigue, joint pain, headache, irritability and

other mood disturbances, and muscle and joint pain. On clinical examination, physical signs of

peripheral neuropathy, including paresthesias and motor weakness may be present (Culen et al.,

1983). Clinical examination is insensitive to central nervous system impairment; however, when

subjected to formal clinical neurobehavioral evaluation, patients with lead intoxication often show

impairment of multiple central nervous system functions (Bordo et al., 1982; Baloh et al., 1980;

Valciukas et al., 1978a. Valciukas et al., 1978b. Stollery et al., 1989; Hanninen et al., 1979;

Mantere et al., 1984; Baker et al., 1985; Ashby, 1980).

Although leaded fuels were used in the Persian Gulf, it is unlikely that exposures to tailpipe

emissions were of sufficient duration or intensity to produce any kind of clinically apparent toxicity

from lead exposure. While long-term exposure to lead does result in accumulation of lead in

long-term storage pools in the human body, short-term exposures result in little long-term

accumulation. Failure of symptoms to remit for years following exposure is inconsistent with lead

as an etiology of unexplained symptoms experienced by some Gulf War veterans. Furthermore,

leaded fuels were used in the United States for decades and are still in use in many other countries

worldwide. No reports of symptoms identical to those experienced by Persian Gulf veterans have

emerged despite such widespread and long-term use.

Depleted uranium is a by-product of the extraction of uranium-235 (U235) from naturally

occurring uranium. Military applications for this material include munitions production (armor

piercing bullets and artillery shells) and armor for tanks and personnel carriers. The PGW was the

first US use, in actual military conflict, of depleted uranium tipped shells and depleted uranium

armored tanks and other vehicles (United States General Accounting Office, 1993).

Page 8

United States Senate Committee on Veterans’ Affairs

164

At the current time, estimates of the total number of military personnel who had any exposure

to depleted uranium are not available. Exposure may have occurred to personnel in vehicles

penetrated by depleted uranium rounds as well as personnel involved in recovery and repair of

vehicles damaged by depleted uranium containing rounds. The Army has identified 35 soldiers who

were injured in combat vehicles damaged by depleted uranium munitions, 22 of whom likely were

wounded by DU containing shrapnel. In addition, 27 soldiers involved in damage assessment and

preparation for shipment of damaged combat vehicles have reported exposure to DU during those

activities (United States General Accounting Office, 1993).

Exposure to uranium, depleted or non-depleted, is not known to produce adverse effects on the

nervous system (Thun et al., 1985; Leggett, 1989; Morris and Meinhold, 1995). Reports of exposure

to depleted uranium to soldiers in the Persian Gulf, although uncertain, suggest limited numbers of

involved personnel. These facts make extremely unlikely that exposure to depleted uranium during

the Gulf War is responsible, wholly or in part, for the array of symptoms observed among Gulf War

veterans.

DEET,the common name for N,N-Diethyl-m-toluamide, is widely regarded as the most effective

topical insect repellent available and is the major active ingredient in virtually all products marketed

for this purpose (Robbins and Cherniack, 1986; Osimitz and Murphy, 1997). It was registered for

use by the general public in 1957 and has been in civilian and military use since then. DEET has

beena remarkably successful commercial product and is currently estimated to be used, in some form,

by approximately 80 million persons in the United States, annually (Stinecipher and Shah, 1997).

Despite relatively long-term use by millions, only a few reports of toxicity were found in the medical

literature. Most descriptions of human toxicity come from case reports of individual exposures or

fromsmall case series. Among the 20 individuals described in case reports, the group most frequently

affected by DEET exposure were children and the most commonly reported effects involved the

nervous system (Osimitz and Murphy, 1997).

Several factors suggest that DEET is not responsible for the symptoms reported by some veterans

of the Persian Gulf War. First, the product appears to have adverse effects only on a very small

proportion of those who use it (Veltri et al., 1994). Second, the main adverse neurological effect

appears to be seizures, a condition not reported commonly among Gulf War veterans, although one

study of occupationally exposed workers has associated DEET with neurological symptoms with some

similarity to those experienced by Gulf War veterans (as reported by Osimitz and Murphy, 1997 and

Robbins and Cherniack, 1986). The symptoms were experienced at the time of exposure to DEET,

however; no long-term follow-up was reported. All clinical studies of adverse effects of DEET

suggest full recovery occurs after withdrawal of exposure. No literature is available to suggest that

topical use of DEET results in long-term health consequences.

Solvents are simple organic substances that are (1) liquid at room temperature, (2) relatively

non-reactive, and (3) able to dissolve a wide range of organic compounds (i.e., lipophilic). Most

Page 9

Report of the Special Investigation Unit on Gulf War Illnesses

165

solvents are quite volatile. The primary uses of solvents in the PGW were as motor vehicle and jet

fuel, carriers for paint and coatings, and as an agent for control of airborne dusts blown from sand.

Solvents can affect the central nervous system (CNS), the peripheral nervous system (PNS), or

both. Short term exposure to organic solvents can cause reversible anesthesia-like depression of the

CNS. Long-term, heavy exposure to solvents may cause persistent, potentially irreversible

impairment in cognitive function and affect, which may be associated with structural changes in

neural tissue (NIOSH, 1987). Solvents can also cause impairment of peripheral nerve function

(Spencer and Schaumburg, 1985).

Peripheral nervous system effects are well-established for a few specific solvents, none of which

appear to have been used in the Persian Gulf (Spencer and Schaumburg, 1985). Acute, reversible

CNS effects (i.e., acute intoxication) are common with all solvents (Laine and Riihim�ki, 1986).

Chronic, apparently fixed, adverse effects of solvents on the CNS have been reported in the

literature, with general agreement that long-term occupational exposure to solvents is associated

with adverse effects on multiple CNS domains and that persons who suffer from such effects may

report symptoms similar to those reported by some Persian Gulf War veterans, including depression,

impaired concentration, and memory loss (Hanninen, 1986; Danish Ministry of the Environment,

1991; Hogstedt, 1994; Spurgeon et al., 1992; Rasmussen et al., 1993; White et al., 1995; Daniell et

al., 1993; H�nninen et al., 1991). The duration and intensity of exposure required to cause such

effects and the potential severity of such effects is somewhat controversial, although most authorities

agree that at least ten years of occupational (daily or near daily) exposure is required before effects

are seen (Mikkelsen et al., 1988). Exposures to organic solvents in the Persian Gulf appear to be of

insufficient duration, and may also have been of insufficient intensity, to produce chronic adverse

effects on the CNS.

In summary, multiple agents with potential toxicity to the nervous system were used by military

personnel in the Persian Gulf War. Such agents include pyridostigmine bromide, chemical warfare

agents (“nerve gas”), pesticides, heavy metals, DEET, and organic solvents. Each of these agents or

class of agents has been associated, in the biomedical literature, with acute or chronic toxicity to the

central or peripheral nervous systems.

Soldiers returning from the Persian Gulf have reported numerous symptoms compatible with

nervous system dysfunction including fatigue, headache, sleep disturbance, depression and memory

impairment.

The concurrence of exposures with potential toxicity to the nervous system and the reporting of

symptoms compatible with nervous system toxicity has lead to considerable scrutiny of a possible

causal association between them. Review of the biomedical literature suggests, at this time, that

neurotoxicity from exposure to pyridostigmine bromide, chemical warfare agents (“nerve gas”),

pesticides, heavy metals, DEET, and organic solvents is not a likely explanation for symptoms

Page 10

United States Senate Committee on Veterans’ Affairs

166

experienced by Persian Gulf War veterans. Reasons for this conclusion vary for each individual

agent or class of agents but include insufficient duration of exposure, evidence of insufficient

intensity of exposure, incompatibility of effects of exposure with symptoms reported by military

personnel, and the chronicity of illness following removal from exposure.

While currently available evidence does not support a neurotoxicological etiology for symptoms

reported by many Persian Gulf War veterans, some key issues remain unclear. To close these gaps

in knowledge, the following recommendations are made:

To better characterize the neurological health status of Persian Gulf War veterans, a large study

of a randomly selected sample of Persian Gulf War veterans and Persian Gulf War era veterans who

did not serve in the Gulf in which objective measures of neurological and neurobehavioral function

are used to assess neurological health should be performed.

Because clinical experience among healthy adults is limited, additional investigation of the

long-term human health effects of pyridostigmine bromide in among healthy adults should be

performed. Should pyridostigmine bromide be used by the US military in future conflicts, accurate

records should be kept to permit fruitful long-term assessment of dose-effect relationships.

To determine whether exposure to pyridostigmine bromide altered military personnel responses

to stress, investigation of the effect of pyridostigmine on physical and psychological responses to

perceived threat of physical harm should be performed.

Because exposure to hazards rarely occurs in isolation, investigation of the effects of combined

exposure to potentially toxic agents used in the Persian Gulf War should be performed. While such

investigationsmay necessarily be performed on animals, the exposures used should be similar in route

of administration, intensity, and duration to those experienced by humans under actual exposure

conditions.

Inthe future, better efforts should be made to characterize objectively both health and hazardous

exposuresamong US military personnel facing hazardous duty. Standardized, objective neurological

and neurobehavioral testing of military personnel before deployment would provide useful baseline

information about health status to which results of repeat testing, following deployment, could be

compared. Quantitative assessment of exposure to potential hazards would provide information to

compare to changes in health status that might be detected. The feasibility of such an effort should

be explored.

REFERENCES

Amato AA, McVey A, Cha C, et al. Evaluation of neuromuscular symptoms in veterans of the

Persian Gulf War. Neurology 48:4-12; 1997.

Page 11

Report of the Special Investigation Unit on Gulf War Illnesses

167

Ames RG, Steenland K, Jenkins B, Chrislip D, Russo J. Chronic neurologic sequelae to

cholinesterase inhibition among agricultural pesticide applicators. Arch Environ Research

50:440-444; 1995.

Ashby JAS. A neurological and biochemical study of early lead poisoning. Brit J Indust Med.

37:133-140; 1980.

Baker EL, White RF, Pothier LJ, Berkey CS, Dinse GE, Travers PH, Harley JP, Feldman RG.

Occupational lead neurotoxicity: improvement in behavioural effects after reduction of

exposure. Brit J Indust Med. 42:507-516; 1985.

Baloh RW, Langhofer L, Brown CP, Spivey GH. Quantitative eye tracking tests in lead

workers. Am J Indust Med. 1:109-113; 1980.

Blick DW, , Murphy MR, Brown GC, Yochmowitz MG, Fantan JW, Hartgraves SL. Acute

behavioral toxicity of pyridostigmine or soman in primates. Toxicol Appl Pharmacol

126:311-318; 1994.

Bordo B, Massetto N, Musicco M, Filippini G, Boeri R. Electrophysiological changes in

workers with “low” blood lead levels. Amer J Indust Med., 3:23-32; 1982.

Burchfiel JL, Duffy FH, Sim VM. Persistent effects of sarin and dieldrin upon the primate

electroencephalogram. Toxicol and Appl Pharmacol 35:365-379; 1976.

Culen MR, Robins JM, Eskenzai B. Adult inorganic lead intoxication: Presentation of 31 new

cases and a review of recent advances in the literature. Medicine. 62:221-247; 1983.

10. Daniell W, Stebbins A, O’Donnell J, Horstman SW, Rosenstock L. Neuropsychological

performance and solvent exposure among car body repair shop workers. Br J Ind Med. 1993;

50:368-377.

11. Danish Ministry of the Environment. Organic Solvents and the Nervous System: Report of a

Conference. Copenhagen: CEC/Danish Ministry of the Environment; 1991.

12. Dirnhuber P, French MC, Green DM, Leadbeater L, Stratton JA. The protection of primates

against soman poisoning by pretreatment with pyridostigmine. J Pharm Pharmacol.

31:295-299; 1979.

13. GrobD, Harvey JC. Effects in man of the anticholinesterase compound sarin (isopropyl methyl

phosphonofluoridate). J Clin Invest 37:350-368; 1958.

Page 12

United States Senate Committee on Veterans’ Affairs

168

14. Haley RW, Hom J, Roland PS, et al. Evaluation of neurologic function in Gulf War Veterans.

JAMA 277:223-230; 1997.

15. Hanninen H, Mantere P, Hernberg S, Seppalainen AM, Kock B. Subjective symptoms in

low-level exposure to lead. Neurotoxicology. 1:333-347; 1979.

16. H�nninen H. Neurobehavioral assessment of long-term solvent effects on man. In: Riihim�ki

V, Ulfvarson U, eds. Safety and Health Aspects of Organic Solvents. New York: Alan R. Liss;

1986; 225-236.

17. H�nninen H, Antti-Poika M, Juntunen J, Koskenvuo M. Exposure to organic solvents and

neuropsychological dysfunction: a study on monozygotic twins. Br J Ind Med. 48:18-25; 1991.

18. Hogstedt C. Has the Scandinavian solvent syndrome controversy been solved? Scand J Work

Environ Health. 1994; 20:59-64.

19. Jamal GA, Hansen S, Apartopoulos F, Peden A. The “Gulf War Syndrome”. Is there evidence

of dysfunction in the nervous system? J Neurol Neurosurg Psychiatry 60:449-451; 1996.

20. Keeler JR, Hurst CG, Dunn MA. Pyridostigmine used as a nerve agent pretreatment under

wartime conditions. JAMA 266:693-695; 1991.

21. KorsakRJ and Sato MM. Effects of chronic organophosphate pesticide exposure on the central

nervous system. Clinical Toxicol 11:83-95; 1977.

22. Laine A, Riihim�ki V. Acute solvent intoxication. In: Riihim�ki V, Ulfvarson U, eds. Safety

and health aspects of organic solvents. New York: Alan R. Liss; 1986; 123-131.

23. Leggett RW. The behavior and chemical toxicity of U in the kidney: A reassessment. Health

Physics. 57:365-383; 1989.

24. Mantere P, Hanninen G, Hernberg S, Luukkonen R. A prospective follow-up study on

psychological effects in workers exposed to low levels of lead. Scand J Work Environ Health.

10:43-50; 1984.

25. Mikkelsen S, J�asorgensen M, Browne E, Gyldensted C. Mixed solvent exposure and organic

brain damage: A study of painters. Acta Neurol Scand. 1988; 78 (suppl 118):1-143.

26. Morris SC, Meinhold AF. Probabilistic risk assessment of nephrotoxic effect of uranium in

drinking water. Health Physics. 69:897-908; 1995.

Page 13

Report of the Special Investigation Unit on Gulf War Illnesses

169

27. NIOSH: Organic Solvent Neurotoxicity. Cincinnati, OH: US DHHS 1987: 1-39. DHHS

publication 87-104.

28. Osimitz TG, Murphy JV. Neurological effects associated with use of the insect repellent

N,N-Diethyl-m-toluamide (DEET). Clinical Toxicol. 35:435-441; 1997.

29. PersianGulf Veterans Coordinating Board. Unexplained illness among Desert Storm veterans.

Arch Int Med 155:262-268; 1995.

30. Presidential Advisory Committee on Gulf War Veterans’ Illness: Final Report (Washington,

DC: US Government Printing Office, December 1996).

31. Rasmussen K, Arlien-Soborg P, Sabroe S. Clinical neurological findings among metal

degreasers exposed to chlorinated solvents. Acta Neurol Scand. 1993; 87:200-204.

32. Robbins PJ, Cherniack MG. Review of the biodistribution and toxicity of the insect repellent

N,N-Diethyl-m-toluamide (DEET). J Toxicol and Environ Health. 18:503-525; 1986.

33. Rosenstock L, Keiffer M, Daniell WE, McConnell R, Claypoole K, et al. Chronic central

nervoussystem effects of acute organophosphate pesticide intoxication. Lancet 338:223-227;

1991.

34. Savage EP, Keefe TJ, Mounce LM, Heaton RK, Lewis JA, Burcar PJ. Chronic neurological

sequelae of acute organophosphate pesticide poisoning. Archiv Environ Health 43:38-45;

1988.

35. Schwartz BS, Ford DP, Bolla KI, et al. Solvent-associated decrements in olfactory function in

paint manufacturing workers. Am J Ind Med. 1990; 18:697--706.

36. Sharabi Y, Danon YL, Berkenstadt H. et al. Survey of symptoms following intake of

pyridostigmine during the Persian Gulf War. Isr J Med Sci 27:656-658; 1991.

37. Sidell FR, Borak J. Chemical warfare agents: II. Nerve agents. Ann Emerg Med 21:865-871.

38. SpencerPS, Schaumburg HH. Organic solvent neurotoxicity: Facts and research needs. Scand

J. Work Environ Health. 1985; 11:53-60.

39. Spurgeon A, Gray CN, Sims J, Calvert I, Levy LS, et al. Neurobehavioral effects of long-term

occupational exposure to organic solvents: two comparable studies. Am J Ind Med. 1992;

22:325-335.

Page 14

United States Senate Committee on Veterans’ Affairs

170

40. Steenland K, Jenkins B, Ames RG, O’Malley M, Chrislip D, Russo J. Chronic neurological

sequelae to organophosphate pesticide poisoning. Am J Public Health 84:731-736; 1994.

41. Stinecipher J, Shah J. Percutaneous permeation of N,N-Diethyl-m-toluamide (DEET) from

commercial mosquito repellents and the effect of solvent. J Toxicol and Environ Health.

52:119-135; 1997.

42. Stollery BT, Banks HA, Broadbent DE, Lee WR. Cognitive functioning in lead workers. Brit

J of Indust Med. 46:698-707; 1989.

43. Thun MJ, Baker DB, Steenland K, Smith AB, Halperin W, Berl T. Renal toxicity in uranium

mill workers. Scand J Work Environ Health. 11:83-90; 1985.

44. United States General Accounting Office. Operation Desert Storm: Army not adequately

prepared to deal with depleted uranium contamination. Washington, DC, 1993.

45. Valciukas JA, Lilis R, Eisinger J, Blumberg WE, Fischbein A, Selikoff IJ. Behavioral indicators

of lead neurotoxicity: results of a clinical field survey. Arch Occup Environ Health.

41:217-236; 1978a.

46. Valciukas JA, Lilis R, Fischbein A, Selikoff IJ, Eisinger J, Blumberg WE. Central nervous

system dysfunction due to lead exposure. Science. 201:465-467; 1978b.

47. Veltri JC, Osimitz TG, Bradford DC, Page BC. Retrospective analysis of calls to poison control

centersresulting from exposure to the insect repellent N,N-Diethyl-m-toluamide (DEET) from

1985 to 1989. Clin Toxicol. 32:1-16; 1994.

48. White RF, Proctor SP, Echeverria D, Schweikert J, Feldman RG. Neurobehavioral effects of

acute and chronic mixed-solvent exposure in the screen printing industry. Am J Ind Med.

1995; 28:221-231.

Page 15

Report of the Special Investigation Unit on Gulf War Illnesses

171

PERSISTENT HEALTH EFFECTS OF PESTICIDES AND OTHER

CHEMICALS USED IN DESERT STORM AND DESERT SHIELD

Prepared by: Matthew Keifer, M.D., M.P.H., Occupational and Environmental Medicine

Program, Departments of Medicine and Environmental Health, Harborview Medical Center,

University of Washington, Seattle, Washington.

his report reviews the classes of pesticides, nerve gas, and prophylactic medication

(pyridostigmine bromide) to which the Gulf War (GW) personnel were exposed, or potentially

exposed, for the possibility that such exposure might be responsible for the chronic health problems

known collectively as the Gulf War Syndrome. Recommendations for future research are also

included.

Several different types of pesticides were imported to the Persian Gulf and acquired locally by

Americanforces during Desert Storm and Desert Shield. While use patterns of neither imported nor

locally acquired pesticides are documented, the quantities of imported pesticides are documented.

Most of the imported pesticides were insecticides or repellents. Pesticides are by nature poisons most

ofwhich affect the nervous system. The potential for long term health effects resulting from exposure

to many of these chemicals has been demonstrated in numerous studies and case reports with the

nervous system being the principal focus of the majority of these reports.

The oganophosphates, a potent class of pesticides, appear to have been imported in large

quantities. These chemicals have been clearly identified in many studies as a cause of both central

and peripheral chronic neurological effects in persons who have sustained a heavy exposure (Keifer

1997,Rosenstock 1991, Steenland 1994, Savage 1988, McConnell 1994, Lotti 1986). It is important

to note that nearly all cases of chronic neurological effects attributed to organophosphates resulted

from overexposure which caused acute severe clinical illness. Most studies of subjects who have

sustained less severe exposures or only chronic low level exposure have not observed these chronic

neurological outcomes (Ames 1995, Fiedler 1997, Engel 1998).

One organophosphate, chlorpyriphos, which was shipped in large quantities (1580 gallons pure

active ingredient, 3841 gallons of formulated product) and has been identified as capable of causing

peripheral neuropathy in human beings following heavy exposure (Lotti 1986, Kaplan 1993), has

recently come under careful scrutiny in the US because of its extremely broad use by both private

citizens and pesticide applicators. The Health Effects Division of the Environmental Protection

Agency reviewed the published literature and unpublished case reports and concluded that

chlorpyriphos “may be a significant cause of chronic neurobehavioral effects”. Unfortunately the

report provided no exposure context in which these “chronic effects” might be expected to occur

Page 16

United States Senate Committee on Veterans’ Affairs

172

(Blondell1997). A recent study of morbidity by investigators from the manufacturer of chlorpyriphos

identified an elevated risk for five diagnostic categories among its employees exposed to

chlorpyriphos: 1. diseases of the ear and mastoid process; 2. acute respiratory infections; 3. other

diseases of the respiratory system; 4. general symptoms, signs, and ill defined conditions; and 5.

symptoms, signs and ill defined conditions involving the digestive system. (Burns et al. 1998). The

illness categories identified by these investigators as showing higher rates in exposed workers reflect

a broad assortment of signs and symptoms but of particular interest is the inclusion of the general

symptoms category (numbers 4, ICD9 780-799).

The medical conditions included in this category are generally those that do not permit strict

disease diagnosis by clinicians but interestingly this symptom category is the same as the third most

common diagnosis identified by the Comprehensive Clinical Evaluation Program (CCEP) in

evaluating 20,000 Persian Gulf veterans (Joseph et al. 1997). This overlap of diagnosis between

workers exposed in an industrial setting and personnel exposed during the Gulf War experience

potentially to the same chemical is intriguing. However, it should be pointed out that the situations

are not directly comparable. How this chemical was used by personnel in the Gulf is not clearly

documented (IOM 1996) where as exposure to the chemical is estimated in the Burns study.

Additionally the workers who were reporting these illnesses through the company medical program

were presumably actively exposed at the time of their reported illnesses and the CCEP study group

was examined and questioned at time when presumably exposure to chlorpyriphos had ceased.

Before conclusions that an excess prevalence of this diagnostic category in the CCEP study

population is reached an adequate control population would be needed. There was no association

drawn in either the EPA report or the morbidity study between chlorpyriphos and peripheral

neuropathy, a condition affecting 0.2% of 20,000 veterans examined by the CCEP (Joseph et al

1997).

The other organophosphate pesticides included in the list of imported pesticides include one,

dichlorvos, which has been identified in animal models as an inducer of peripheral neuropathy.

However this chemical as used in the Gulf was enclosed in pest strips making significant

overexposure less likely. No reports were found in the literature that environmental exposure to

these pest strips caused significant illness or peripheral neuropathy.

The N-methyl-carbamates were imported in large quantities and while sharing the acute

toxicological characteristics of organophosphates, have only rarely been associated with persistent

health effects, and then only after chronic heavy exposure (Ecobichon et al 1982). The carbamates

are in the same family of chemicals as pyridostigmine, the chemical used to prophylax personnel

against nerve gas in the gulf. The pyrethroids, another category of pesticides, were brought over in

large quantities, but are of relatively low acute toxicity and appear to be relatively safe pesticides

(Aldridge 1990, He 1994).

Page 17

Report of the Special Investigation Unit on Gulf War Illnesses

173

Aluminum phosphide, a fumigant, was also imported in substantial quantities (20,020 tablets).

These chemical tablets produce phosphine gas when combined with water. Phosphine is a very toxic

gas which can produce severe illness in the setting of sufficient exposure. The illness produced by

phosphine exposure would not be easily overlooked (Morgan 1989). Furthermore, based on how

aluminum phosphide is generally used it is highly unlikely that low dose exposure to phosphine

occurred. There is no evidence in the literature that chronic illness results from low dose exposure

to phosphine.

In the absence of massive overexposure, each of these pesticides by itself, organophosphates, n-

methyl-carbamates and pyrethroids, or phosphine, is not likely to have resulted in chronic health

effects among even a substantial minority of U.S. troops.

Diethyl-m-toluamide (DEET) was imported in large quantities and presumably used widely as an

insect repellent during the conflict (DOD on Aug 27, 1997 to Senator A. Specter). It is also widely

used by the U.S. population in general and given its broad use (30+ % of the US population), the

chemical has a reasonably good safety record (Veltri 1994). Case reports indicate that this chemical

can induce central nervous system effects when absorbed in sufficient quantity but cases usually

involve excessive exposure and often involve young children or infants. No reports in the literature

describe the long term toxicity of DEET among humans with low level chronic exposure though

some permanent residual effects have been noted in at least one case following recovery from what

appeared to be an acute intoxication (Knowles 1992). The possibility that even relatively heavy

exposure to DEET alone could induce chronic health effects in the Gulf personnel is unlikely.

Pyridostigmine bromide (PB), used by the U.S. forces as a prophylactic agent against the toxicity

of nerve gas has demonstrable toxicity for both animal models and humans when given in relatively

high dosage. The standard 30 mg three time per day dosage provided to U.S. forces may have caused

acute toxicity in particularly susceptible populations such a asthmatics or soldiers with a unique

serum cholinesterase phenotype (Loewenstein-Lichtenstein 1995), or in soldiers who received high

per weight dosage because of small body mass (Gouge 1994) but this dosage has been shown to be

generally well tolerated by the majority of the population (Blick 1994, Borland 1985, Cook 1992,

Glikson 1991).

Studies on animals suggests that under stressful situations the lack of central nervous system

penetration which makes PB an attractive prophylactic may not be assured. This central nervous

system penetration may lead to acute central nervous system symptoms. Symptom persistence

resulting from this increased penetration has not been reported to date in human or animal models,

although evidence from one study presented indicated that a central nervous system feedback

mechanism may account for changes which may outlast the acute cholinergic effects of the drug

(Freidman et al 1996).

Page 18

United States Senate Committee on Veterans’ Affairs

174

No information was found as to whether the bromide in the preparation might have had

deleterious effects given bromide’s long half-life and the desert conditions of chronic high heat and

salt depletion. Despite these caveats, the years of experience in treating patients for myasthenia

gravis with PB at doses often much higher than those taken by Gulf War service personnel would

suggest that the development of persistent health effects among Gulf War personnel from PB alone

isunlikely. The pyridostigmine is rapidly metabolized and the bromide is excreted over several weeks

once the drug administration is stopped. The penetration of the blood brain barrier by

pyridostigmine under the stress of a combat situation may potentially result in acute effects given

sufficient blood levels, but with metabolism of the drug and the reversal of the acute effects, it is

unlikely that long term effects would ensue.

The health effects of exposure to nerve gases has been only periodically addressed in the

mainstream literature. One excellent study which examined most of the important nerve gases for

production of peripheral neuropathy showed that sarin was capable only at super-lethal doses of

potentiallyinducing neuropathy (Gordon et al. 1983). Few cases of known human exposure to nerve

gases are available to examine for long term effects, so predictions must be modeled mostly from

animal experiments. The Center for Disease Control concluded in 1988 that there appeared to be

little risk of adverse health effects from low level long-term exposure to GA, GB, VX, H, HD, HT

or lewisite (CDC 1988). In a review of the literature on nerve agents, Gunderson et al. concluded

that persistent effects such as psychological and behavioral problems, could result after acute

exposure, but that no evidence supported persistent effects from low level exposure to these

chemicals (Gunderson et al.1992). A recently published study on survivors of the Japanese subway

sarin gas incidents identifies possible delayed effects on balance among surviving female victims.

These authors also cite an as yet unpublished manuscript identifying neurobehavioral abnormalities

among other victims 6-8 months after the poisoning (Yokoyama et al. 1998). These findings are

consistent with problems identified among persons previously poisoned with organophosphate

pesticides (Keifer et al. 1997, Steenland et al.1994, Rosenstock et al. 1991, McConnell et al. 1994,

Savage et al.1980, Lotti et al. 1986), which are related to the military nerve gases. The literature

does not provide evidence to support persistent neurological or other health effects from low-level

exposure to nerve gases.

From the information presently available, it does not appear that the DOD has a policy for

monitoring cholinesterase or for assessing the physiological effects of the prescribed standard

prophylactic dose of pyridostigmine bromide. The broad application of cholinesterase monitoring

for all those taking PB doses would probably not be beneficial. Most people taking the drug would

probably have a very predictable response to the dosage. The drug generally appears to be safe when

takenby individuals of average size (70 kg), with normal uninhibited cholinesterase activity and with

no illnesses which would make them particularly susceptible to ill effects from the PB. However,

there is a substantial minority of individuals who may be smaller in stature, have illnesses such as

asthma or, in rare cases, have congenitally low cholinesterase which makes them sensitive to PB even

when taken in the prescribed dose. A mechanism should be in place to identify those who might

Page 19

Report of the Special Investigation Unit on Gulf War Illnesses

175

suffer ill effects and determine how their dosage should be adjusted in order to avoid complications

while still providing protection from nerve gases.

Cholinesterase monitoring has long been used among pesticide applicators to identify

overexposure to organophosphates. It also can potentially be used to identify personnel exposed to

organophosphate nerve gas. Accurate interpretation requires a pre-exposure baseline on a subject

against which to compare subsequent values. This limitation, and problems with the accuracy of

commerciallyavailable test kits, makes cholinesterase testing complicated. Recently, a new approach

to identifying overexposure to organophosphate nerve gas has been described. This method

reactivates inhibited cholinesterase and reconstitutes the nerve gas molecule which can then be

measured (Polhuijs et al. 1997). If this technique shows itself to be sound, it has potential

application in determining whether personnel have sustained exposure to nerve gas even several

weeks after exposure.

The potential for chronic health effects resulting from mixtures of chemicals and from mixtures of

pyridostigmine bromide and pesticides is a subject of interest and recent investigation, though relatively

little has been published to date. Studies on laboratory animals have demonstrated that in sufficient

dosage, damage to the nerves of the body can occur with mixtures of some of the chemicals used by

service personnel in the Gulf War conflict (Abou donia 1996a & b). An important caveat to these

studies is that the dosages used to induce these damages were well above what would have been

expected to occur by regular use of these chemicals. Studies of the effects of DEET on the absorption

of pyrethroids and carbaryl (an n-methyl-carbamate) do not support the contention that more

chemical is absorbed in the presence of DEET (Baynes et al 1997).

SUMMARY

fair degree of uncertainty surrounds the exposures that may have occurred to personnel during

Desert Shield and Desert Storm. Nevertheless, based on the information available in the

literature regarding the pesticides and anti-personnel chemicals to which troops may have been

exposed in the GW, chronic health effects would not be expected in any significant number due to

low level exposure to these chemicals or to combinations of these chemicals. A small percentage of

the population may have had reactions to these chemicals not predicted by animal research or

human studies and given exposure sufficient to result in acute toxicity, chronic problems would not

be surprising. Information sited in this report does raise questions about the possible non-specific

symptoms reported by a substantial percentage of CCEP subjects and how this might relate to

pesticide exposures which occurred in GW personnel. This relationship is uncertain but intriguing.

The use of PB by the Gulf War personnel would probably not cause significant illness in most

individuals but might cause problems in some with small stature, asthma or unique biochemistry.

The two greatest limitations in identifying illness due to exposures in a theater of war are the virtual

absence of exposure information and the difficulty of evaluating the health status of a self-selected

group. In future conflicts, better collection of exposure information and prospective follow-up of a

Page 20

United States Senate Committee on Veterans’ Affairs

176

statistically valid sample of the combatant population with an appropriate non-combatant control

group would facilitate the identification and characterization of emerging illnesses.

RECOMMENDATIONS

sincere and scientifically valid effort to explore and address health concerns of veterans from

military conflicts is an extremely important responsibility that our government has toward its

veterans. But communicating in an open, non-defensive manner with the concerned service

personnel and the public about the state of knowledge and the progress of knowledge is potentially

the greatest challenge facing the Department of Defense and the Veterans Administration with

regard to issues of post conflict health of veterans. While the health problems from which Gulf War

veterans suffer may never be completely ascribed with certainty to specific exposures that occurred

during service in the Gulf, the challenge of identifying, and caring for the health of veteran’s and

responding to the health concerns of veterans will continue as long as there are veterans. Effective

risk communication is essential to maintaining and optimized three way dialog between the veteran-

active duty community, the citizenry and the responsible government branches.

SPECIFIC RECOMMENDATIONS

his author can not substantially improve on the scientific comprehensiveness of the

recommendations made by the Institute of Medicine on improving the surveillance and

monitoringcapabilities of the DOD regarding health effects of combat service (Institute of Medicine,

IOM,1996). I do believe it is important to add that the IOM report fails to recommend a mechanism

whereby the veterans, the U.S. public and active duty personnel might participate in the functioning

of an ongoing system of health outcomes monitoring. Potentially the most important predictor of

success of this program as judged by these constituencies is the degree to which they can claim

ownership of the process. I strongly encourage that a mechanism be established to assure active

participation by representatives of the U.S. public, veterans groups and active duty personnel of

varied ranks and branches in the design and conduct of any program that is adopted. A mechanism

should also be established to regularly communicate with all veterans providing them with ongoing

information about new developments and knowledge regarding the effect of service and health.

RESEARCH IN BASIC AND APPLIED SCIENCE

upport for further research on technology for detecting environmental release and personal

exposure to war gases should be a particular emphasis of the DOD. Monitors should be

developed that are portable, collect and report real time information, and have data storage

capabilities and are easily applied by combatants.

Page 21

Report of the Special Investigation Unit on Gulf War Illnesses

177

Research should be undertaken to develop profiles of individuals who may potentially suffer

untoward effects from war gas antidotes (e.g. asthmatics, smaller individuals). Those individuals

should have personal drug dosing profiles developed and confirmed by cholinesterase activity levels

appropriate to the prophylactic medication taken. Routine cholinesterase testing of all personnel

is probably not warranted, but the test should be available on a routine basis for evaluating ill

combatants both for overdose of prophylactic medication and for evaluating war gas exposure.

A new technique described by Polhuijs (1997) potentially represents a very significant

breakthrough in the detection of cholinesterase inhibited by the nerve gas sarin. Whether this

technique is applicable to other nerve gases and pesticides has not been demonstrated to date. This

technique should be explored and amplified if possible for application to exposure assessment of

subjects potentially exposed to nerve gases and pesticides.

REFERENCES

Abou-Donia MB, Wilmarth KR, Abdel-Rahman AA, Jensen, KF, Oehme FW, Kurt TL:

Increasedneurotoxicity following concurrent exposure to pyridostigmine bromide, DEET, and

chlorpyrifos. Fundam Appl Toxicol 1996; 34:201-222.

Abou-Donia MB, Wilmarth KR, Jensen KF, Oehme FW, Kurt TL: Neurotoxicity resulting

from coexposure to pyridostigmine bromide, DEET, and permethrin: Implications of Gulf War

chemical exposures. J Toxicol Environ Health 1996; 48(1):35-56.

Aldridge WN. An assessment of the toxicological properties of pyrethroids and their

neurotoxicity. Crit Rev Toxicol 1990; 21(2):89-104

Ames RG, Steenland K, Jenkins B, Chrislip D and Russo J. Chronic neurologic sequelae to

cholinesteraseinhibition among agricultural pesticide applicators. Arch Environ Health 1995;

50:440-444.

Baynes R, Halling K, Riviere J. The influence of diethyl-m- tolumamide (DEET) on the

percutaneous absorption of permethrin and carbaryl. Toxicol. Appl. Pharmacol. 1997;

144:332-339.

Blick DW, Murphy MR, Brown GC, Yochmowitz MG, Fanton JW and Hartgraves SL. Acute

behavioral toxicity of pyridostigmine or soman in primates. Toxicol Appl Pharmacol 1994;

126:311-318.

Blondell J. Environmental Protection Agency Office of Prevention , Pesticides and Toxic

Substances. Memorandum: Review of Chlorpyriphos Poisoning Data. Jan 14, 1997.

Page 22

United States Senate Committee on Veterans’ Affairs

178

Borland RG, Brennan DH, Nicholson AN and Smith PA. Studies on the possible central and

peripheraleffects in man of a cholinesterase inhibitor (pyridostigmine). Human Toxicol 1985;

4:293-300.

Burns C, Cartmill J, Powers B, Lee M. Update of the morbidity experience of employees

potentially exposed to chlorpyriphos. Occup Environ Med 1998; 55:65-70.

10. Center for Disease Control. 53 FR 8504 Final Recommendations for Protecting the Health and

Safety Against Potential Adverse Effects of Long-Term Exposure to Low Doses of Agents:

GA,GB,VX,Mustard Agent,(H, HD, T) and Lewisite (L). Tuesday March 15, 1988.

11. Ecobichon D and Joy R. Pesticides and Neurological Diseases, Florida: CRC Press, 1982.

12. Engel L, Keifer M, Checkoway H, Robinson L, Vaughan T. Neurophysiological Function in

Farm Workers Exposed to Organophosphate Pesticides. Arch Environ Hlth (Archives of

Environmental Health 53(1):7-14.

13. Fiedler N, Kipen H, Kelly-McNeil K, Fenske R. Long-term use of organophosphates and

neuropsychological performance Am J. Industrial Med. 1997; 32:487-496.

14. Friedman A, Kaufer D, Shemer J, Hendler I, Soreq H and Tur-Kaspa I. Pyridostigmine brain

penetration under stress enhances neuronal excitability and induces early immediate

transcriptional response. Natur Med 1996; 2(12):1382-1385.

15. Gordon J, Inns R, Johnson M, Leadbeater L, Maidment M, Upshall D, Cooper G, Rickard R.

Thedelayed neuropathic effects of nerve agents and some other organophosphorus compounds.

Arch Toxicol 52: 71-82; 1983.

16. Gunderson C, Lehmann C, Sidell F, Jabbari B, Nerve Agents: A review. Neurology 42:946-950;

1992.

17. He F. Synthetic pyrethroids. Toxicol 1994; 91(1):43-49.

18. Institute of Medicine Report Health Consequences of Service During the Persian Gulf Ware:

Recommendations for Research and Information Systems. National Academy Press.

Washington, 1996.

19. Johnson MK. Delayed neurotoxicity - do trichlorphon and/or dichlorvos cause delayed

neuropathy in man or in test animals? Acta Pharmacol Toxicol Copenh 1981; 49(5):87-98.

Page 23

Report of the Special Investigation Unit on Gulf War Illnesses

179

20. Joseph A C. A comprehensive clinical evaluation of 20,000 Persian Gulf War veterans.

Comprehensive Clinical Evaluation Program Evaluation Team. Mil-Med. 1997 Mar. 162(3).

P 149-55.

21. Kaplan JG, Kessler J, Rosenberg N, et al:. Sensory neuropathy associated with Dursban

exposure. Neurology 1993; 43:2193-2196.

22. KeiferM C. Mahurin R K. Chronic neurologic effects of pesticide overexposure. Occupational

Medicine. 1997 Apr-Jun. 12(2). P 291-304.

23. Knowles C. Chapter 22 Miscellaneous Pesticides in Handbook of Pesticide Toxicology eds

Hayes W, and Laws E. 1991. Center for Disease Control. Final Recommendations for

Protecting the Health and Safety of Against Potential Long -Term exposure to Low Doses of

Agents; GA,GB, VX, Mustard Gas (H,HD,T) and Lewisite (L). 53 FR 8504 CDC March 15,

1988.

24. Lotti M, Moretto A, Zoppellari R, Dainese R, Rizzuto N and Barusco G. Inhibition of

lymphocytic neuropathy target esterase predicts the development of organophosphate-induced

delayed polyneuropathy. Arch Toxicol 1986; 59(3):176-179.

25. Loewenstein-Lichtenstein Y, Schwarz M, Glick D, N_rgaard-Pendersen, Zakut H and Soreq

H. Genetic predisposition to adverse consequences of anti-cholinesterase in ‘atypical’ BCHE

carriers. Nat Med 1995; 1(10):1082-1085.

26. McConnellR, Keifer M and Rosenstock L. Elevated quantitative vibrotactile threshold among

workers previously poisoned with methamidophos and other organophosphate pesticides. Am

J Ind Med 1994; 25(3):325-334.

27. MorganD. Recognition and Management of Pesticide Poisonings. Fourth edition. March 1989

EPA-540/0-88.

28. Report: The quantities of pesticides ordered based on records of the Defense General Supply

Center. Letter to Sen. Arlen Specter Aug 27, 1997.

29. RosenstockL, Keifer M, Daniell WE, McConnell R and Claypoole K. Chronic central nervous

system effects of acute organophosphate pesticide intoxication. The Pesticide Health Effects

Study Group. Lancet 1991; 338(8761):223-7.

30. Savage EP, Keefe TJ, Mounce LM, Lewis JA, Heaton RK and Parks, LH. Chronic neurological

sequelaeof acute organophosphate pesticide poisoning: A case-control study. Epidemiological

Page 24

United States Senate Committee on Veterans’ Affairs

180

StudiesProgram, Health Effects Brance, Hazard Evaluation Division of the U.S. Environmental

Protection Agency, Washington, D.C., 1980.

31. SteenlandK, Jenkins B, Ames R G, O’Malley M, Chrislip D and Russo J. Chronic neurological

sequelae to organophosphate pesticide poisoning. Am J Public Health 1994; 84(5):731-736.

32. Polhuijs M, Langenberg J, Benschop H. New method for retrospective detection of exposure

to organophosphorus anticholinesterases: application to alleged sarin victims of Japanese

Terrorists. Toxicol. Appl. Pharmacol. 146, 156-161. 1997.

33. Veltri J, Pharm D, Osimitz T, Bradford D, Page B. Retrospective Analysis of calls to poison

control centers resulting from exposure to the insect repellent n,n-diethyl-m-toluamide

(DEET) from 1985-1989. Clinical Toxicology 1994; 32(1),1-16.

34. Yokoyama K, Araki S, Murata K, Nishikitani M, Okumura T, Ishimatsu S, Takasu N. A

preliminary study on delayed vistibulo-cerebellar effects of Tokyo subway sarin poisoning in

relation to gender difference: frequency analysis of postural Sway. JOEM 40(1): 17-20, 1998.

Page 25

Report of the Special Investigation Unit on Gulf War Illnesses

181

POSSIBLE POTENTIATION OF PYRIDOSTIGMINE BROMIDE

BY PESTICIDES

Prepared by: James Moss, Ph.D., Gainesville, Florida

SUMMARY

he Senate Committee on Veterans’ Affairs requested a review and analysis of research on

synergism or potentiation of pyridostigmine bromide (PB) toxicity by pesticides. This summary

examines reports that indicate PB may become more toxic when an organism is simultaneously

exposed to pesticides and other factors. This report suggests that PB has the potential to affect

multiple organs and tissues, and that pesticides may synergise or potentiate the effects of PB on

various organs and tissues. The author feels that knowledge of which pesticides and other chemicals

potentiate PB toxicity will eventually lead to an understanding of the mechanism(s) underlying the

observed interactions. When these mechanisms are understood, clearer scientific judgement, and

hypothesis based models, can be used so that we may better understand whether PB may contribute

tochronic illnesses. Knowledge of which biochemical systems are responsible for pesticide synergism

of PB toxicity may allow avoidance of complications of PB use.

Introduction. Pyridostigmine bromide (PB) is a quaternary dimethyl carbamate that has been

usedto treat myasthenia gravis, a neuromuscular disorder characterized by skeletal muscle weakness

(Breyer et al. 1990). Since 1986, PB has been recommended by the United States Army as a

prophylactic agent for organophosphate (OP) nerve gas exposure (Dunn and Sidell 1989).

Organophosphates bind irreversibly to the enzyme acetylcholinesterase (AChE) in the central (CNS)

and peripheral (PNS) nervous systems and thereby prevent hydrolysis (breakdown) of the chemical

neurotransmitter acetylcholine (ACh). As a result, ACh accumulates at nerve and muscle receptor

sites. At muscles, this can produce excessive stimulation leading ultimately to muscle paralysis and

death.

A prophylactic dose of PB (30 mg, every eight hours) binds to AChE, thereby protecting the

enzyme from permanent damage by OP chemical warfare agents. Over time the PB is released and

AChE activity is restored to a level needed to maintain life, providing that atropine and oxime

treatments are also administered at the time of nerve gas exposure (Cook and Kolka 1992). This

protocol has been shown to protect primates from the chemical warfare nerve agent Soman

(von-Bredow et al. 1991, Wolfe et al. 1992).

Page 26

United States Senate Committee on Veterans’ Affairs

182

Synergism (Potentiation). The possibility that PB could play a role in chronic illnesses increases

if conditions potentiate (synergize) PB’s toxicity. Such conditions might include simultaneous

exposure to other chemicals/toxins such as pesticides. A simultaneous exposure to a toxin and

another chemical can produce several different outcomes. These outcomes can range from no

increased toxicity, an additive effect or a synergistic effect.

An additive effect is the sum of the independent effects of the chemicals. A dose of “A” may kill

5% of a population and a dose of “B” may kill 5% of a population. The effects would be additive if

the same doses of “A” and “B” killed 10% of the population when given together.

Synergism, or potentiation, is an interaction that gives a more than additive effect. In a

synergistic interaction, a dose of “A” that killed 5% of a population plus a dose of “B” that killed 5%

of a population would kill over 10% and up to 100% of the population, when given together.

When used for nerve gas protection, PB was designed to be taken at doses that would inhibit

about30% AChE activity (Cook and Kolka 1992). Studies have shown that some pesticides increase

PB’s toxicity from about two-fold to ten-fold (Moss 1996) (Abou-Donia et al. 1996a) (McCain et

al. 1997). Even low level potentiation of this specific PB action (AChE inhibition) might inhibit a

large proportion of AChE activity, which could be fatal. Any degree of synergism of the effects of

PB is therefore relevant.

PB’s Effects Outside of Acetylcholinesterase Inhibition (Side Effects). It is possible to have

substantial AChE inhibition by some chemicals without a resulting chronic illness. Several hundred

humans were exposed to the AChE inhibitor sarin (nerve gas) at doses which caused cholinergic

symptoms and substantial AChE inhibition (Sadayoshi et al. 1997), yet the authors reported that

chronic delayed effects associated with poisoning by some other OPs were not present.

As mentioned above, PB’s main action is acetylcholinesterase (AChE) inhibition. If PB’s only

actionis AChE inhibition, and AChE inhibition is found unlikely to contribute to chronic symptoms,

then the likelihood that PB can contribute to chronic illnesses is diminished. However, a different

outcomeis possible if, in addition to AChE inhibition, PB has some other specific action (side effect).

If such a side effect were able to produce chronic outcomes, synergism of the side effect would

increase the chronic outcomes. In this review, “side effect” means those effects which are the result

of a chemical’s action on a molecular target other than the presumed or known primary target for

that chemical. For PB, this means effects that are the result of PB actions on a molecular target other

than acetylcholinesterase. Possible side effects of PB, may be important if the side effects are

potentiated by the actions of pesticides or other factors. Such a potentiation would cause the side

effects to increase relative to the known cholinergic effects of PB, and might produce unexpected

outcomes.

Page 27

Report of the Special Investigation Unit on Gulf War Illnesses

183

PB’S Muscarinic Side Effects. ACh causes two major types of response: nicotinic (nicotine

sensitive)and muscarinic (muscarine sensitive) (Bowman and Rand 1980). PB produces more of one

typeof ACh induced response (muscarinic) over the other (nicotinic) (Arce et al. 1991, De-Novellis

et al 1994, Muller et al. 1991). This predominantly muscarinic effect would not occur if PB’s only

action was acetylcholinesterase (AChE) inhibition, because blocking of AChE should elevate ACh

at both nicotinic and muscarinic receptors equally. One would not expect to see one or the other

effect to predominate. PB is known to directly affect cellular Ach receptors in addition to AChE

inhibition (Pascuzzo et al. 1984), and PB binds to ACh muscarinic receptors (Yamamoto et al. 1996).

PB therefore has one side effect of activating muscarinic receptors, in addition to its ability to inhibit

AChE.

PB’s Calcium Side Effects. LoPachin and Lehning (1997) stated that “Studies conducted over

thepast two decades indicate that calcium accumulation in injured axons has significant neuropathic

implicationsand is a potentially unifying mechanistic event.” PB induced muscle damage is probably

caused by calcium leakage into cells through calcium channels, because a calcium channel blocker

was able to reduce PB induced muscle damage (Meshul 1989).

PB’S Neurotoxic Esterase Side Effects. Another potential side effect target of PB is on an

enzyme called neurotoxic esterase (NTE). NTE inhibition is believed to be associated with

organophosphate induced delayed neuropathy (OPIDN). Some OP acetylcholinesterase inhibitors

(in addition to their AChE inhibition), also inhibit NTE, and such exposure can lead to OPIDN

(delayed neuropathy) in experimental animals (Lotti et al. 1993).

Many OPs inhibit both AChE and NTE (Ehrich et al. 1995). The type of toxic effect can range

from purely AChE inhibition (rapid death from respiratory failure), to mostly delayed neuropathy

(causedby NTE inhibition) (Lotti et al. 1993). Mixed effects can be exhibited by a single compound.

Selectivesynergism of the NTE effect would result in selection for OPIDN symptoms over cholinergic

symptoms. An example of this type of chemical manipulation was the production of OPIDN in cats

by chlorpyrifos which normally causes only cholinergic symptoms (Fikes et al. 1992).

PBis a carbamate, and an AChE inhibitor. Some carbamates (in addition to AChE) inhibit NTE

and therefore have the potential to cause delayed neuropathy if given chronically, or at high doses.

A carbamate (PMBC) has been shown to cause delayed neuropathy in hens with repeated doses

(Lotti et al. 1993). A series of other carbamates have been synthesized that also inhibit NTE

(Randall et al. 1997). Carbaryl, a carbamate pesticide, has been reported to cause delayed

neuropathy in a human (Dickoff et al. 1987). PB therefore has the potential to inhibit NTE and

synergism of that side effect is a possible route to PB induced delayed neuropathy.

Target Organs. PB has predominately muscarinic side effects and many organs and tissues are

affected by muscarinic, cholinergic chemicals such as PB (Bowman and Rand 1980). Many organs

and tissues are therefore potential targets of synergised, muscarinic, side effects of PB. Examples are

Page 28

United States Senate Committee on Veterans’ Affairs

184

the human central nervous system (CNS) which has PB sensitive, muscarinic receptors (Valcavi et

al, 1991, Mazza et al. 1994, O’Keane et al. 1992). PB does not easily cross the blood-brain barrier

(BBB)under “normal” conditions, however, the BBB may be more permeable under some conditions

such as stress (Friedman et al. 1996). The BBB is not completely impermeable to PB, under any

circumstances. PB causes CNS mediated behavioral changes in rats (Wolthuis and Vanwersch

1984), rhesus monkeys (Blick et al. 1994) and humans (Borland et al. 1985). Chronic dosing of PB

resulting in a constant exposure of the BBB could result is significant amounts of PB in the CNS.

Other examples of organs and tissues that have muscarinic receptors which are potential targets

of PB effects are peripheral neural tissue such as the guinea pig myenteric plexus (Mike 1994) and

the rat superior cervical sympathetic ganglion (Ramcharan and Matthews 1996). There are also

muscarinic receptors in the hearts of humans (Bowman and Rand 1980) and in blood vessels in the

human brain (Tsukahara et al. 1989a), human skin (Stephenson and Kolka 1990), rat mesenteric

vascularbed (Pinardi et al. 1992), the rabbit thoracic aorta (Tsukahara et al. 1989b) and the rat liver

(Pfaffendorf and Van-Zwieten 1993). Other organs or tissues that are sensitive to muscarinic effects

arethe retina (Hutchins 1994) the eye’s ciliary body (Farahbakhsh and Cilluffo 1994), salivary gland

(Iwabuchi and Masuhara 1992), pancreas (Kato et al. 1992), tracheal smooth muscle (Thomas and

Ehlert 1996), adrenal cells (Aguilar et al.1992), gut smooth muscles (Reddy et al. 1995), the spleen

(Sandberg, 1994), kidney cells (Mohuczy and Garg 1992), the bladder (Kumamoto et al. 1990),

gallbladder smooth muscle (von-Schrenck et al. 1993) and lung (Mak et al. 1992). Immune system

cells (thymocytes and lymphocytes) are also sensitive to muscarinic chemicals (Kubera et al. 1992).

Potential Pesticide Synergists of PB Toxicity. This table is a partial list of pesticides ordered

through the federal supply system for operations Desert Shield and Desert Storm (U.S. Senate

1995b). The insecticides with question marks (?) have not yet been evaluated for the ability to

potentiate the toxicity of PB.

Pesticide

Insecticide Class

Synergizes PB?

permethrin

pyrethroid

yes

chlorpyrifos

organophosphate

yes

lindane

organochlorine

yes

DEET

repellant

yes

propoxur

carbamate

carbaryl

carbamate

diazinon

organophosphate

Page 29

Report of the Special Investigation Unit on Gulf War Illnesses

185

dichlorvos

organophosphate

methomyl (Fly bait)

carbamate

malathion

organophosphate

pyrethrins

pyrethroid-like

Of these insect control chemicals, DEET, permethrin and lindane are designed to be used in a

manner that was likely to involve close personal human contact. Interest in the synergism of PB by

DEET and permethrin arose as a result of disclosures to the U.S. Senate Veterans’ Affairs Committee

(U.S. Senate 1995a) that DEET and permethrin caused increased PB toxicity in cockroaches.

Abou-Donia et al. (1996b) recently reported that the organophosphate insecticide chlorpyrifos, PB,

and DEET interact synergistically.

The pesticides discussed below potentiate PB toxicity in various animals. Little is known about

thespecific mechanisms of these synergistic mechanisms. It will be difficult to predict whether these

interactions would cause chronic health consequences until the specific mechanisms of synergistic

interactions are understood.

Permethrin. Permethrin is a pyrethroid insecticide. Pyrethroids are generally thought to kill by

modifying sodium channel function in nerve fibers. This leads to excessive leakage of sodium ions

in nerve fibers which leads to excessive depolarization and excitation of the neurons (Matusmura

1985). Pyrethroid insecticides can also directly inhibit an enzyme that removes (pumps) calcium

from inside cells of the rat brain (Alrajhi1990). Combined effects of PB (increased calcium leakage

into the cells) plus permethrin (blocked calcium removal by pumps) could lead to a co-synergistic

increaseby these chemicals on cellular calcium. The outcome would be potentiation, by permethrin,

of PB induced damage. Calcium loading, and subsequent damage, would be possible in tissues that

had muscarinic (PB) receptors and permethrin sensitive calcium pumps.

PB toxicity is potentiated by permethrin in cockroaches (Moss 1996), chickens (Abou-Donia et

al. 1996a), and rats (McCain et al. 1997). It is not clear whether this potentiation was caused by

permethrin’s actions on sodium channels, calcium pumps, or another action of permethrin.

Abou-Donia et al. (1996a) suggested that, in chickens, PB prevented the breakdown of permethrin,

that the permethrin action was responsible for the toxicity, and that PB was simply increasing the

permethrinconcentration (and therefore its effect). However, the damage and clinical signs reported

in this study (Abou-Donia et al. 1996a) were similar to the results of organophosphate induced

delayed neuropathy (OPIDN) and not pyrethroid poisoning. In addition to this, Buchholz et al.

(1997) found that when rats were simultaneously dosed with PB and permethrin, PB caused the

central nervous system tissue levels of permethrin to be lowered by 30%.

Page 30

United States Senate Committee on Veterans’ Affairs

186

Eitherpyrethroid mechanism (sodium or calcium disruption) can lead to an ion imbalance within

nerve cells which can lead to over-excitation and eventual direct damage to the nerves (LoPachin

and Lehning (1997)). This over-excitation also leads to an inappropriate release of neurochemicals

from nerves that leads to secondary physiological effects (Bowman and Rand 1980). Any of these

permethrin effects have the potential to synergise the primary action of PB, or PB’s known and

potentialside effects. The long term consequences of a simultaneous exposure to PB and permethrin

cannot be predicted without knowledge of which biochemical effects are responsible for the

synergism of PB toxicity.

Chlorpyrifos. Chlorpyrifos is an organophosphate (OP) insecticide which inhibits

acetylcholinesterase. It can also cause organophosphate-induced delayed neuropathy (OPIDN)

(Fikes et al. 1992). Because OPIDN may be related in some way to the disruption of calcium levels

in cells (Abou-Donia 1993), the possibility also exists that some interaction between PB and

chlorpyrifos is from the effects of both compounds on calcium maintenance in nerve cells.

PB and chlorpyrifos potentiate the toxicity of each other in chickens. A suggested reason for this

wasthat both compounds block a detoxifying esterase enzyme that breaks down both chemicals. The

neuropathy was attributed to the action of chlorpyrifos which was synergized because its breakdown

was prevented by PB (Abou-Donia et al. (1996b). The authors suggested that these combined

chemicals may be responsible for some manifestations of chronic illnesses in Persian Gulf War

veterans. It was also suggested that the neuropathy seen was not from the effects of neurotoxic

esterase (NTE) inhibition, but the symptoms reported were consistent with the effects of neurotoxic

esterase (NTE) inhibition (Lotti et al. 1993, Johnson 1990).

Other Pesticides. Other pesticides may have been locally obtained. Those from the OP,

carbamate and pyrethroid classes of pesticides have the potential to synergize PB toxicity because of

similar modes of action. No information was found that ruled out or confirmed synergism of PB

toxicity by those pesticides.

DDT is available outside of the U.S. and may have been present in the Persian Gulf. DDT does

not strictly fit into the above classes, however, the mode of action of DDT is close to that of the

pyrethroids in insects and vertebrates (Matusmura 1985). PB potentiates the toxicity of DDT in

cockroaches and DDT may potentiate PB toxicity (Moss, unpublished data). It is therefore possible

that DDT would also be a PB synergist in mammals.

Lindane. Lindane is a common organochlorine de-lousing agent. Lindane toxicity is potentiated

fourteen fold in cockroaches by a sub-lethal dose of PB (Moss, unpublished data). No published

researchwas found that dealt with synergism between PB and lindane on vertebrates. Lindane blocks

inhibitory actions in the nervous system which results in over-excitation (Matusmura 1985). One

of the side effects of lindane is the inhibition of a calcium ATPase, a pump that removes calcium

from cells (Basavarajappa and Salimath 1990). Combined effects of PB (increased calcium leakage)

Page 31

Report of the Special Investigation Unit on Gulf War Illnesses

187

plus lindane (blocked calcium removal by pumps) would probably lead to a co-synergistic increase

by these chemicals on cellular calcium. The outcome would be potentiation, by lindane, of PB

induced damage. Calcium loading, and subsequent damage, would be possible in tissues that had

muscarinic (PB) receptors and lindane sensitive calcium pumps. Synergistic interactions between

PB and lindane in vertebrates should be investigated.

DEET (N,N-Diethyl-m-toluamide). The insect repellant DEET was developed by the U.S.

Department of Agriculture in the 1950's (McCabe et al. 1954). The mechanism(s) of the repellant

and toxic action(s) of DEET are still unknown. Some reports indicate that excessive doses of DEET

may be toxic to humans (Clem et al. 1993, Lipscomb et al.1992, Schaefer and Peters 1992) and

non-human vertebrates (Mount et al. 1991, Schoenig et al. 1993, Verschoyle et al. 1992).

DEET and PB synergize each other’s toxicity in cockroaches (Moss 1996), rats (McCain et al.

1997), chickens (Abou-Donia et al. 1996a), and mice (Chaney et al. 1997a). In chickens, the

synergism of DEET has been attributed to blocking of degrading enzymes (esterases) by PB so that

more DEET could cross the blood-brain barrier (BBB) (Abou-Donia et al. 1996a).

We cannot understand the sub-lethal, possible long term consequences of this chemical mixture

of PB and DEET without knowing DEET’s mode of action. One cannot tell from current

experiments which of the two (DEET or PB), is the primary toxicant, the synergist, or if both

contribute to synergism and toxicity.

Moss (1996) hypothesized that DEET might have actions similar to the insect neurochemical

octopamine, or the human neurochemical adrenaline. Based on that speculation, Chaney et al.

(1997a,b)tested the ability of both DEET, adrenaline, and adrenergic drugs to potentiate the toxicity

of PB. Chaney et al.(1997a) found that both DEET and beta-adrenergic drugs (including the native

neurochemical adrenaline) synergised the toxicity of PB in mice. The synergistic interactions

between PB and DEET, and PB and adrenergic drugs, were probably caused by the muscarinic side

effectsof PB because atropine (a muscarinic receptor blocker) eliminated the synergistic interactions

(Chaney et al. 1997a). DEET’s synergism of PB toxicity may be the result of adrenergic effects of

DEET.

The possibility that PB will synergise the effects of adrenergic stimulation should also be

investigated. In preliminary experiments (J. Moss and J. Schiffenbauer, unpublished data) it was

found that PB and salbutamol (a beta-adrenergic PB synergist in mice [Chaney et al. 1997a,b])

interacted synergistically in mouse T-lymphocytes. Combined, PB and salbutamol inhibited mouse

T-cell proliferation while the same drugs alone had no effect. Adrenergic drugs were originally

investigated because DEET mode of action research raised the possibility that DEET had adrenergic

effects. The effects on lymphocytes might range from subtle short-term effects which could be

stimulation or suppression, depending on the particular type and stage of development of the cells

or the effect could be outright mortality of the cells.

Page 32

United States Senate Committee on Veterans’ Affairs

188

REFERENCES

Abou-Donia, M.B. 1993. The cytoskeleton as a target for organophosphorus ester-induced

delayed neurotoxicity (OPIDN). Chem. Biol. Interact. 87(1-3): 383-93. Abou-Donia, M.B.,

Wilmarth, K.R., Jensen, K.F., Oehme, F.W., Kurt, T.L.. 1996a. Neurotoxicity resulting from

coexposure to pyridostigmine bromide, deet, and permethrin: implications of Gulf War

chemical exposures. J. Toxicol. Environ. Health. 48(1): 35-56.

Abou-Donia, M.B., Wilmarth, K.R., Abdel-Rahman, A.A., Jensen, K.F., Oehme, F.W., Kurt,

T.L. 1996b Increased neurotoxicity following concurrent exposure to pyridostigmine bromide,

DEET, and chlorpyrifos. Fundam. Appl. Toxicol. 34(2): 201-22.

Aguilar, J.S.,Ballesta, J.J.,Reig, J.A.,Palmero, M., Viniegra, S., Criado, M. 1992. Muscarinic

Receptor Subtypes in Bovine Adrenal Medulla (Neurochem. Res. 17(12): 1235-1239.

Alrajhi, D.H. 1990. Properties of Ca-2+- Mg-2+-ATPase from Rat Brain and Its Inhibition

by Pyrethroids. Pestic. Biochem. Physiol. 37: 116-120.

Arce, V.M., Cella, S.G., Locatelli, V., Muller, E.E. 1991. Studies of growth hormone secretion

in calorically restricted dogs: effect of cholinergic agonists and antagonists, glucose and

thyrotropin-releasing hormone. Neuroendocrinology. 53(5): 467-72.

Basavarajappa,B.S. Salimath, B.P. 1990. Inhibition of Calmodulin-Dependent Enzymes in Rat

Brain by Hexachlorocyclohexane. Pesticide Science 29: 397-404.

Blick, D.W., Murphy, M.R., Brown, G.C., Yochmowitz, M.G., Fanton, J.W., Hartgraves, SL.

1994. Acute behavioral toxicity of pyridostigmine or soman in primates. Toxicol. Appl.

Pharmacol. 126(2): 311-8.

Borland, R.G., Brennan, D.H., Nicholson, A.N., Smith, P.A. 1985. Studies on the Possible

Central and Peripheral Effects in Man of a Cholinesterase Inhibitor (Pyridostigmine). Human

Toxicol. 4:293-300.

Bowman, W. C., Rand, M.J. 1980. Textbook of pharmacology, 2nd ed. Blackwell, Oxford.

10. Breyer-Pfaff, U., Schmezer, A., Maier, U. 1990. Neuromuscular function and plasma drug levels

inpyridostigmine treatment of myasthenia gravis. J. Neurol. Neurosurg. Psychiatry 53: 502-506.

11. Buchholz, B.A., Pawley, N.H., Vogel, J.S. & Mauthe, R.J. 1997. Pyrethroid decrease in central

nervous system from nerve agent pretreatment. J. Appl. Toxicol. 17(4): 231-234.

Page 33

Report of the Special Investigation Unit on Gulf War Illnesses

189

12. Chaney, L., Moss, J., Mozingo, J., & A. Hume. 1997a. Toxic interactions between

pyridostigmine (PB), N,N-Diethyl-m-toluamide (DEET), adrenergic agents and caffeine.

Toxicologist 36(1), P2, p21, #106.

13. Chaney, L.A., Mozingo, J.R., Hume, A.S. & J.I. Moss. 1997b. Potentiation of Pyridostigmine

Bromide Toxicity in Mice by Selected Adrenergic Agents and Caffeine. Vet. Human Toxicol.

39(4): 214-219.

14. Clem,J. R., Havemann, D.F., Raebel, M.A. 1993. Insect repellent (N,N-diethyl-m-toluamide)

cardiovascular toxicity in an adult. Ann. Pharmacother. 27: 289-293.

15. Cook, J.E. and Kolka, M.A. 1992. Chronic pyridostigmine bromide administration: side effects

among soldiers working in a desert environment. Mil Med 157: 250-254.

16. De-Novellis,V., Cuparencu, B., Elthes, L., Sandor, V., Mangrella, M., Imperatore, A., Guarino,

V., Stella, L. 1994. The failure of pyridostigmine to influence the coronary artery spasms

induced by vasopressin in conscious rabbits. Curr. Ther. Res. 55:102-7.

17. Dickoff, D.J., Gerber, O., Turovsky, Z. 1987. Delayed neurotoxicity after ingestion of

carbamate pesticide. Neurology. 37: 1229-31.

18. Dunn, M.A. and Sidell, F.R. 1989. Progress in medical defense against nerve agents. JAMA

262: 649-652.

19. Ehrich, M., Jortner, B.S., Padilla, S. 1995. Comparison of the Relative Inhibition of

Acetylcholinesterase and Neuropathy Target Esterase in Rats and Hens Given Cholinesterase

Inhibitors. Fund. Appl. Toxicol. 24:94-101.

20. Farahbakhsh, N.A., Cilluffo, M.C. 1994. Synergistic effect of adrenergic and muscarinic

receptor activation on [Ca2+]i in rabbit ciliary body epithelium. J. Physiol.(London).

477:215-21.

21. Fikes, J.D., Zachary, J.F., Parker, A.J., Beasley, V.R. 1992. Clinical, Biochemical,

Electrophysiologic, and Histologic Assessment of Chlorpyrifos Induced Delayed Neuropathy

in the Cat. Neurotoxicology. 13:663-678.

22. Friedman,A., Kaufer, D., Shemer, J., Hendler, I., Soreq, H., Tur-Kaspa, I. 1996. Pyridostigmine

brain penetration under stress enhances neuronal excitability and induces early immediate

transcriptional response. Nat. Med. 2(12): 1382-5.

Page 34

United States Senate Committee on Veterans’ Affairs

190

23. Hutchins, J.B. 1994. Development of muscarinic acetylcholine receptors in the ferret retina.

Dev. Brain Res. 82:45-61.

24. Iwabuchi, Y., Masuhara, T. 1992. Subtype of the Muscarinic Receptor That Mediates Salivary

Secretion in the Rat Sublingual Gland. Asia Pacific Journal of Pharmacology. 7:197-202.

25. Johnson, M.K. 1990. Organophosphates and delayed neuropathy is NTE alive and well?

Toxicol. Appl. Pharmacol. 102:385-399.

26. Kato, M., Ohkuma, S., Kataoka, K., Kashima, K., Kuriyama, K. 1992. Characterization of

Muscarinic Receptor Subtypes on Rat Pancreatic Acini - Pharmacological Identification by

Secretory Responses and Binding Studies. Digestion 52:194-203.

27. Kubera,M., Skowron, C.A., Mazur, K.B., Bubak, S.M., Basta, K.A., Laskowska, B.H., Ryzewski,

J. 1992. Stress-induced changes in muscarinic and.beta.-adrenergic binding sites on rat

thymocytes and lymphocytes. J. Neuroimmunol; 37:229-35.

28. Kumamoto, E., Shinnick, G.P. 1990. Action of an irreversible acetylcholine esterase inhibitor,

soman, on muscarinic hyperpolarization in cat bladder parasympathetic ganglia. Br. J.

Pharmacol. 99:157-63.

29. Lipscomb, J. W., Kramer, J.E., Leikin, J.B. 1992. Seizure following brief exposure to the insect

repellent N,N-diethyl-m-toluamide. Ann. Emerg. Med. 21:315-317.

30. LoPachin, R.M., Lehning, E.J. 1977. Mechanism of Calcium Entry during Axon Injury and

Degeneration. Toxicol. Appl. Pharmacol. 143:233-244.

31. Lotti, M., Moretto, A., Capodicasa, E., Bertolazzi, M., Peraica, M., Scapellato, M. L. 1993.

Interactions between neuropathy target esterase and its inhibitors and the development of

polyneuropathy. Toxicol. Appl. Pharmacol. 122:165-171.

32. Mak, J.C.W., Baraniuk, J.N., Barnes, P.J. 1992. Localization of Muscarinic Receptor Subtype

messenger RNAs in Human Lung. Am. J. Respir. Cell and Mol. Biol. 7:344-348.

33. Matusmura, F. 1985. Toxicology of insecticides. Plenum Press, New York.

34. Mazza, E., Ghigo, E., Boffano, G., Valetto, M., Maccario, M., Arvat, E., Bellone, J., Procopio,

M., Muller, E.E., Camanni, F. 1994. Effects of direct and indirect acetylcholine receptor

agonists on growth hormone secretion in humans. Eur. J. Pharmacol. 254:17-20.

Page 35

Report of the Special Investigation Unit on Gulf War Illnesses

191

35. McCabe, E. T., Berthel, W.F., Gertler, S.I., Hall, S.A. 1954. Insect Repellents. III. J. Org.

Chem. 19:493-498.

36. McCain, W.C., Lee, R., Johnson, M.S., Whaley, J.E., Ferguson, J.W., Beall, P., Leach, G. 1997.

Acute oral toxicity study of pyridostigmine bromide, permethrin, and DEET in the laboratory

rat. J. Toxicol. Environ. Health. 50:113-24.

37. Meshul, C.K. 1989. Calcium channel blocker reverses anticholinesterase-induced myopathy.

Brain. Res. 497:142-8.

38. Mike, A. 1994. Possible mechanisms of the effect of physostigmine on the facilitation of

acetylcholine release in the guinea pig myenteric plexus. Brain. Res. Bull. 34:441-5.

39. Mohuczy, D.D., Garg, L.C. 1992. Muscarinic receptors in MDCK cells are coupled to multiple

messenger systems. Am. J. Physiol. 263(Pt.1):C1289-C1294.

40. Moss, J.I. 1996. Synergism of Toxicity of N,N-Diethyl-m-toluamide to German Cockroaches

(Othoptera: Blattellidae) by Hydrolytic Enzyme Inhibitors. J. Econ. Entomol. 89:1151-1155.

41. Mount,M.E., Moller, G., Cook, J., Holstege, D.M., Richardson, E.R., Ardans, A. 1991. Clinical

illness associated with a commercial tick and flea product in dogs and cats. Vet. Hum. Toxicol.

33:19-27.

42. Muller, E.E., Locatelli, V., Ghigo, E., Cella, S.G., Loche, S., Pintor, C., Camanni, F. 1991.

Involvement of brain catecholamines and acetylcholine in growth hormone deficiency states.

43. Pathophysiological, diagnostic and therapeutic implications. Drugs. 41:161-77.

44. O’Keane, V., O’Flynn, K., Lucey, J., Dinan, T. G. 1992. Pyridostigmine-induced growth

hormoneresponses in healthy and depressed subjects: evidence for cholinergic supersensitivity

in depression. Psychol. Med. 22:55-60.

45. Pascuzzo, G.J., Akaike, A., Maleque, M.A., Shaw, K. P., Aronstam, R.S., Rickett, D.L.,

Albuquerque, E.X. 1984. The nature of the interactions of pyridostigmine with the nicotinic

acetylcholinereceptor-ionic channel complex. I. Agonist, desensitizing, and binding properties.

Mol. Pharmacol. 25:92-101.

46. Pfaffendorf, M., VanZwieten, P.A. 1993. Mediation by the same muscarinic receptor subtype

of phasic and tonic contractile activities in the rat isolated portal vein. Br. J. Pharmacol.

108:132-8.

Page 36

United States Senate Committee on Veterans’ Affairs

192

47. Pinardi, G., Pelissier, T., Fernandez, E., Bustamante, D., Miranda, H.F. 1992. Pharmacological

Characterization of Muscarinic Receptors in the Rat Mesenteric Vascular Bed. Neurosci. Res.

Commun. 11:57-64.

48. Ramcharan, E.J., Matthews, M.R. 1996. Autoradiographic localization of functional muscarinic

receptors in the rat superior cervical sympathetic ganglion reveals an extensive distribution

over non-synaptic surfaces of neuronal somata, dendrites and nerve endings. Neuroscience

(Oxford). 71:797-832.

49. Randall, J.C., Ambroso, J.L., Groutas, W.C., Brubaker, M.J., Richardson, R.J. 1997. Inhibition

ofNeurotoxic Esterase in Vitro by Novel Carbamates. Toxicol. Appl. Pharmacol. 143:173-178.

50. Reddy,H., Watson, N., Ford, A.P.D.W., Eglen, R.M. 1995. Characterization of the interaction

betweenmuscarinic M2 receptors and.beta.-adrenoceptor subtypes in guinea pig isolated ileum.

Br. J. Pharmacol. 114:49-56.

51. Sadayoshi O., A. Yamashina, N. Takasu, T. Yamaguchi, T. Murai, K. Nakano, Y. Matsui, R.

Mikami, K. Sakurai and S. Hinohara. 1997. Sarin Poisoning on Tokyo Subway. Southern

Medical Journal 90 (6):587-593.

52. Sandberg, G. 1994. Leukocyte mobilization from the guinea pig spleen by muscarinic

cholinergic stimulation. Experientia. 50:40-3.

53. Schaefer, C. Peters, F.W. 1992. Intrauterine diethyltoluamide exposure and fetal outcome.

Reprod. Toxicol. 6:175-176.

54. Schoenig, G.P., Hartnagel, R.E. Jr., Schardein, J.L., Vorhees, C.V. 1993. Neurotoxicity

evaluation of N,N-diethyl-m-toluamide (DEET) in rats. Fundam. Appl. Toxicol. 21:355-365.

55. Stephenson, L.A., Kolka, M.A. 1990 Acetylcholinesterase inhibitor, pyridostigmine bromide,

reduces skin blood flow in humans. Am. J. Physiol. 258(4 Pt 2):R951-7.

56. Thomas, E.A., Ehlert, F.J. 1996. Involvement of the M2 muscarinic receptor in contractions

of the guinea pig trachea, guinea pig esophagus, and rat fundus. Biochem. Pharmacol.

51:779-88.

57. Tsukahara, T., Kassell, N.F., Hongo, K., Vollmer, D.G., Ogawa, H. 1989a. Muscarinic

cholinergic receptors on the endothelium of human cerebral arteries. J. Cereb. Blood Flow

Metab. 9:748-53.

Page 37

Report of the Special Investigation Unit on Gulf War Illnesses

193

58. Tsukahara, T., Hongo, K., Kassell, N.F., Ogawa, H. 1989b. Characterization of muscarinic

cholinergic receptors on the endothelium and the smooth muscle of the rabbit thoracic aorta.

J. Cardiovasc. Pharmacol. 13:870-8.

59. U.S. Senate. 1995a. Is Military Research Hazardous th Veterans’ Health? Lessons from World

War II, The Persian Gulf, and Today. Transcript of Hearing before the Committee on

Veterans’ Affairs,May 6 1994.

60. U.S. Senate. 1995b. Reproductive Hazards and Military Service: What are the Risks of

Radiation, Agent Orange, and Gulf War Exposures? Transcript of Hearing before the

Committee on Veterans’ Affairs, August 5 1994.

61. Valcavi,R., Dieguez, C., Zini, M., Page, .M.D., Dotti, C., Portioli, I., Scanlon, M.F. 1991. Effect

of pyridostigmine and pirenzepine on GH responses to GHRH in hyperthyroid patients. Clin.

Endocrinol. 35:141-4.

62. Verschoyle, R.D., Brown, A.W., Nolan, C., Ray, D.E., Lister, T. 1992. A comparison of the

acute toxicity, neuropathology, and electrophysiology of N,N-diethyl-m-toluamide and

N,N-dimethyl-2,2-diphenylacetamide in rats. Fundam. Appl. Toxicol. 18:79-88.

63. von-Bredow, J.D., Adams, N.L., Groff, W.A., Vick, J.A. 1991. Effectiveness of oral

pyridostigmine pretreatment and cholinolytic-oxime therapy against soman intoxication in

nonhuman primates. Fundam. Appl. Toxicol. 17:761-70.

64. von-Schrenck, T., Sievers, J., Mirau, S., Raedler, A., Greten, H. 1993. Characterization of

muscarinic receptors on guinea pig gallbladder smooth muscle. Gastroenterology. 105:1341-9.

65. Wolfe,A.D., Blick, D.W., Murphy, M.R., Miller, S.A., Gentry, M.K., Hartgraves, S.L., Doctor,

B.P.1992. Use of Cholinesterases as Pretreatment Drugs for the Protection of Rhesus Monkeys

Against Soman Toxicity. Toxicol. Appl. Pharmacol. 117:189-193.

66. Wolthuis, O.L., Vanwersch, R.A. 1984. Behavioral changes in the rat after low doses of

cholinesterase inhibitors. Fundam. Appl. Toxicol. 4(2 Pt 2):S195-208.

67. Yamamoto,K., Shimizu, M., Ohtani, H., Hayashi, M., Sawada, Y., Iga, T. 1996. Toxicodynamic

analysis of cardiac effects induced by four cholinesterase inhibitors in rats. J. Pharm. Pharmacol.

48:935-9.

Page 38

United States Senate Committee on Veterans’ Affairs

194

A DISCUSSION OF ISSUES CONCERNING THE ROLE OF

STRESS IN VETERANS’ REPORTING OF SYMPTOMS

FOLLOWING DEPLOYMENT TO THE GULF WAR

Prepared by: Richard Letz, Ph.D., Department of Behavioral Sciences and Health Education,

Rollins School of Public Health of Emory University, Atlanta, Georgia; and Peachtree

Environmental Consultants, Inc.

THE PAC FINDING THAT STRESS IS LIKELY RELATED TO ILLNESSES IN

SOME GULF WAR VETERANS

he Presidential Advisory Committee on Gulf War Veterans’ Illnesses (PAC) found that (1) many

Gulf War veterans have illnesses that are likely to be connected to their service in the Gulf, (2)

current scientific evidence does not support the hypothesis that Gulf War veterans current illnesses

were caused by a number of environmental risk factors, and (3) stress manifests in diverse ways and

is likely to be an important contributing factor to the broad range of illnesses currently reported by

Gulf War veterans (PAC, 1996, executive summary). Little new scientific information has emerged

in the year following the report’s release to question these findings with respect to the symptoms

reported by large numbers of Gulf War veterans.

The PAC’s conclusion regarding the likelihood that many Gulf War veterans illnesses may be

stress-related may appear to be a “diagnosis by exclusion” due to their findings that the available

scientific evidence did not support hypotheses that other major exposure possibilities were

responsible for the broad spectrum of symptoms reported by many Gulf War veterans. However, one

may argue that “stress” is the only potential exposure that could manifest as the wide variety of

symptoms reported by a large proportion of the Gulf War veterans examined.

Unfortunately, little scientifically sound information for making this argument is to be found in

the literature of studies performed on Gulf War veterans concerning the role of stress in the

symptoms that they report. There is substantial confusion in the Gulf War illness literature

concerning the role of stress. In part, this confusion may stem from a lack of clarity from the larger

stress literature concerning the role(s) that stress plays in the occurrence of physical diseases and,

more particularly, in the types of non-specific symptoms that have been reported frequently by Gulf

Warveterans. No doubt, some of the confusion in the Gulf War illness literature stems from authors’

lack of precision in the use of language concerning stress. Some confusion probably stems from the

language in the PAC final report that virtually equates “stress-related disorders” with psychological

symptoms (PAC, 1996, pp. 73-79). Further, most of the available literature focuses on Post-

Page 39

Report of the Special Investigation Unit on Gulf War Illnesses

195

Traumatic Stress Disorder (PTSD, defined below), rather than the impact that sustained physical

and psychological stressors may have had on veterans’ health and symptom reporting.

WHAT IS STRESS?

tressis defined as a process in which environmental demands tax or exceed the adaptive capacity

of an organism, resulting in psychological and biological changes that may place persons at risk

fordisease (Cohen, Kessler & Gordon, 1995, p.3). It is important to distinguish between components

of the stress process by referring to environmental components as environmental demands, stressors,

or events; to subjective evaluations of stressfulness of a situation as appraisals or perceptions of stress;

and to affective, behavioral, and biological responses to stressors or appraisals as stress responses

(paraphrased from Cohen, Kessler & Gordon, 1995, p.4).

In the general stress literature there are three broad traditions of research of assessing the role of

stress in disease risk (after Cohen, Kessler & Gordon, 1995):

Environmental: a focus on assessment of environmental events that are objectively

associated with substantial adaptive demands.

Psychological: a focus on individuals subjective evaluations of the stressfulness of a

situation and their abilities to cope with those demands.

Biological: a focus on the biological systems activated by psychologically and physically

demanding situations.

The environmental stressors in the Gulf War environment have been addressed in several

investigations. Deployed veterans reported experiencing significant levels of stress in the Persian

Gulf and continued distress upon returning home (Strech et al., 1996). Potential difficulties with

usingcombat exposure questionnaires developed for the Vietnam War veterans to measure exposure

among Gulf War veterans has been discussed, and previously developed questionnaires were modified

to fit better the Gulf War experiences (e.g., see Wolfe, Brown & Kelley, 1993). Even though the

casualty rate was low and the combat period was brief, the threat of chemical/biological warfare

agents is noteworthy, as is the use of large numbers of National Guard / Reservists, who made rapid

transitions both from and back to civilian life. There seems to be little argument that Gulf War

military personnel experienced exposure to substantial physical and psychological stressors in

addition to actual combat: heat, crowding, long periods of idle activity but high arousal, abrupt

dislocation from family and work, the threat of chemical and biological weapons attacks, etc.

Much of the psychological approach in the general stress research has focused on cognitive-

emotional theories of stress, e.g., the transactional model of stress and coping (Lazarus & Folkman,

1984): Stressful experiences are construed as transactions between the person and the environment

Page 40

United States Senate Committee on Veterans’ Affairs

196

in which the impact of a stressor is mediated by the person’s appraisal of the stressor and the coping

resources as his/her disposal. The person evaluates the potential threat or harm of the stressor

(primary appraisal) as well as his/her ability to change the situation or manage negative emotional

reactions (secondary appraisal). Coping efforts are aimed at problem and emotional management.

The outcomes of the coping process are functional status and psychological well-being. Mediators

of both coping efforts and outcomes include the individual’s dispositional coping style and social

support (paraphrased from Lerman & Glanz, 1997). These concepts and theories have been

incorporatedinto the military’s models of combat stress (e.g., Gal & Jones, 1995), stress measurement

instruments used in health studies, and undoubtedly underlie the stress reaction prevention efforts

of the U.S. Army’s Combat Stress Control Detachments (mentioned in PAC report, 1996, pp. 26-

27).

Much of the biological literature on stress in humans has focused on the measurement of

biological(hormonal, physiological, and immunological) stress responses (Cohen, Kessler & Gordon,

1995). A useful review of the neurobiological and endocrinological aspects of the “stress system” and

conceptual linkages to pathophysiology and medical disorders is given by Chrousos & Gold (1992).

The most convincing work in the stress literature has linked stressors to hormonal responses (Baum

& Grunberg, 1995), heart disease (Krantz & Falconer, 1995) and immunological changes (Herbert

& Cohen, 1993; Kiecolt-Glaser JK and Glaser, 1995). Little work on biological stress responses has

been reported among Gulf War veterans, although one DOD-funded project of this type is ongoing

(DOD #31).

In the past, the military has (understandably) focused on two areas of research with respect to

the effects of stressors. One major area of military research has been investigation of the effects of

environmentaland psychological stressors (e.g., sleep deprivation, heat) on military job performance,

i.e., the ergonomic impact of a wide variety of physical and psychological stressors. The other focus

has been medical in nature. Military medical researchers have tended to focus on the effects of

combatstressors in the production of psychiatric casualties such as acute combat reactions and acute

PTSD,i.e., psychiatric disease resulting from experiencing extremely psychologically stressful events

(Jones, 1995). Also understandably, the Department of Veterans Affairs has focused on the

treatment of chronic PTSD.

WHAT IS PTSD?

ost-traumatic stress disorder is a type of anxiety disorder in which the patient has experienced or

witnessed or was confronted with an unusually traumatic event that has both of the following

elements: the event involved actual or threatened death or serious injury to the patient or to others,

and the patient felt intense fear, horror, or helplessness (APA, 1987). The traumatic events have

to be outside the range of usual experience (e.g., combat, rape, floods, abductions, and airplane

crashes, but not “ordinary” life experiences such as bereavement, divorce, and serious illness) which

most people would consider extremely traumatic. The disorder is characterized by (1) repeated re-

Page 41

Report of the Special Investigation Unit on Gulf War Illnesses

197

experiencing the traumatic event (e.g., through flashbacks or repeated distressing dreams), (2)

persistent avoidance of stimuli associated with the trauma and numbing of general responsiveness,

(3) persistent increased arousal not present before the event, (4) these symptoms have lasted longer

than one month, and (5) these symptoms cause clinically important distress or impair work, social,

or personal functioning. There is most often a delay of onset of the symptoms. Acute PTSD refers

to symptoms that have lasted less than six months and chronic PTSD to symptoms lasting longer

than six months. Common symptoms of PTSD patients may include sleep difficulties, exacerbation

of drug/alcohol abuse, outbursts of anger, reduced social activity, and difficulty concentrating on

tasks. Comorbidity with other psychiatric conditions occurs frequently. New to DSM-IV (APA,

1994) is the diagnosis category of “Acute Stress Disorder”, which has similar criteria and symptoms

to PTSD, although the symptoms develop immediately after the traumatic event and last for a few

days to four weeks. The diagnosis of PTSD or acute stress disorder is made by a qualified psychiatrist.

A number of studies indicate that some proportion of Gulf War veterans have experienced

symptoms compatible with PTSD (e.g., Perconte et al., 1993; Ross & Wonders, 1993; Sloan et al.,

1995; Sutker et al., 1993). These research reports of Gulf War veterans have typically involved

measurement of “symptoms of PTSD” or research case definitions derived from self-reported

questionnaire scales. When others have referred to these studies (and sometimes in the reports of

the studies themselves), the term “symptoms of PTSD” has often been shortened to just “PTSD”.

Such imprecision in language promotes confusion. Since these symptoms may not be specific to

PTSD, and it is often not clear that study participants had experienced traumatic events in the Gulf

War of the nature and intensity required for a diagnosis of PTSD, it is probably better to refer to the

outcomes measured in these studies as simply “psychological symptoms” rather than “symptoms of

PTSD”.

The preoccupation with the concept of PTSD has also lead to arguments in the literature not

central to investigating the role of stress in the reporting of symptoms by Gulf War veterans. For

example, it has lead to a misguided attempt to show that the prevalence of PTSD among Gulf War

veterans is not sufficient to support the notion that stress is the cause of all of the veterans symptoms

(Haley, 1997). In fact, no study has been designed and conducted to adequately estimate the

prevalenceof PTSD among Gulf War veterans. Combining data from a number of studies, no matter

how many, that were not designed and implemented properly to estimate the prevalence of a

condition will not yield useful prevalence estimates. Also, surely the PAC’s finding that stress is

likelyto be an important contributing factor to the broad range of illnesses currently reported by Gulf

War veterans is not rebutted by a demonstration that the prevalence of one potentially stress-related

outcome, “symptoms compatible with PTSD”, may not be as high as some authors have reported.

The pre-occupation with the concept of PTSD whenever the role of stress in the symptoms of

Gulf War veterans is discussed has helped to obscure the fact that virtually all differences observed

betweenmilitary personnel deployed to the Persian Gulf and appropriate comparison groups has been

Page 42

United States Senate Committee on Veterans’ Affairs

198

in the self-reporting of physical and psychological symptoms. It seems more prudent to ask: What

symptoms have been reported by Gulf War veterans and how might they be stress-related?

WHAT SYMPTOMS HAVE MANY GULF WAR VETERANS REPORTED?

ulf War veterans have been observed to have a wide variety of health complaints. The most

frequent primary diagnoses in the DOD’s Comprehensive Clinical Evaluation Program were

psychological conditions (18.4%), musculoskeletal conditions and connective tissue diseases

(18.3%), symptoms, signs and ill-defined conditions (17.9%), respiratory system diseases (6.8%),

digestive system diseases (6.3%), skin diseases (6.2%), and nervous system diseases (5.7%), while only

9.7% were found to be healthy. Conditions were counted differently in the VA’s Registry, but a

compatible pattern was observed. Patterns of symptom reporting quite compatible with the pattern

of these categories have been observed in several epidemiologic studies of deployed and non-deployed

Gulf War era military personnel (e.g., Iowa Study Group, 1997; Stretch et al., 1995).

It should be noted that the proportions of participants given above that were assigned each

primarydiagnosis illustrates the relative frequencies withinthe self-referred clinical samplesand can not

begeneralized to the Gulf War population. Similarly, proportions of participants reporting symptoms

in most of the other epidemiologic studies may be over-estimates of population prevalences, given

the substantial participant self-selection in all of those studies except the Iowa study (Iowa Study

Group, 1997).

In general, findings of diseases or abnormalities on objective measures of health status of Gulf era

military personnel have not been observed in any of the few methodologically sound studies. One

large-scale mortality study observed only an increase in unintentional illnesses among Gulf era

military personnel (Kang & Bullman, 1996). Similarly, a large-scale study of morbidity

(hospitalizations) among Gulf War veterans indicated no substantial excess of unexplained

hospitalization among those who remained on active duty following the war (Gray et al., 1996).

Other smaller studies, even among relatively self-selected or clinical groups, have shown no

substantial increased abnormalities on objective neurologic (Newmark & Clayton, 1995),

neuropsychological (Goldstein et al., 1995), and neuromuscular (Amato et al., 1997) tests among

Gulf War veterans.

WHAT DO WE KNOW ABOUT THE REPORTING OF PHYSICAL

SYMPTOMS IN GENERAL?

elf-reported symptoms are important sources of information in clinical medicine. In

epidemiologic studies, they can be important outcomes when measured at the same time as other,

objective measurements of health outcomes. In any case, they are subject to potential reporting bias

and limitations of interpretation. The reporting of physical symptoms is moderated by a number of

Page 43

Report of the Special Investigation Unit on Gulf War Illnesses

199

factors. The following is a list of moderators of physical symptom reporting adapted from the

presentation of Pennebaker (1994):

Individual factors:

! Gender: Females are more likely to report symptoms than males.

! Negative affectivity: Individuals with a history of reporting negative moods are more likely

to report symptoms

! Traumatic experiences in childhood: Individuals with a history of traumatic experience in

childhood are more likely to report symptoms

! Recent traumatic experiences: Individuals experiencing psychological upheavals (death of

a family member, divorce, loss of job) in the past 6 months are more likely to report symptoms

Perceptual factors:

! Boring or tedious environment: amplifies bodily sensations

! Situations fraught with tension or anxiety: conflict at home or at work

! An appropriate trigger or causal attribution: new information about potentially harmful

exposures

Social factors:

! Isolation at home or work: leaves more time to ponder bodily sensations, may increase

anxiety, and not allow social comparison of experiences

! Social spread of the disorder: occurs along friendship lines

! Secondary gain: e.g., attention or relief from work or home responsibilities.

WHAT IS DISTINCTIVE ABOUT THE SYMPTOMS REPORTED BY GULF

WAR VETERANS?

lthough there have been some attempts to define “Gulf War illness” as a syndrome (e.g., Haley,

Kurt & Horn, 1997), there is nothing unique about the spectrum of physical and psychological

symptoms reported by a substantial proportion of returning Gulf War veterans. These symptoms are

Page 44

United States Senate Committee on Veterans’ Affairs

200

frequentlyreported by healthy samples of normal individuals (Pennebaker, 1982). This constellation

of symptoms is similar to that reported by many groups: patients diagnosed with somatization

disorders (e.g., Robbins & Kirmayer, 1991); those meeting case definitions for Chronic Fatigue

Syndrome, fibromyalgia, and Multiple Chemical Sensitivity (Buchwald & Garrity, 1994); Spanish

Toxic Oil Syndrome sufferers (Lopez-Ibor et al., 1985); and a substantial proportion of populations

exposed to natural and man-made disasters such as floods, earthquakes, and large fires (Bromet &

Dew,1995), radiation releases (Baum et al., 1983), and environmental chemical releases (Dayal al.,

1994). Further, it appears that similar symptoms have been reported by a proportion of all

combatants in the U.S. military at least since the Civil War (Hyams, Wignall & Roswell, 1996).

It seems that a viable working hypothesis about what may be similar across this wide variety of

exposures and conditions is stress.

HOW CAN WE KNOW WHETHER STRESS IS CONTRIBUTING FACTOR

TO SYMPTOMS REPORTED BY GULF WAR VETERANS?

nfortunately, most of the studies of health outcomes of Gulf War veterans have not been

designed or implemented in such a way that scientifically defensible inferences can be made

about any likely cause (including stress) of illnesses among Gulf War veterans. The large clinical

registry studies (VA Registry and CCEP) have provided valuable information about the symptoms

that a large number of self-selected Gulf War veterans have, but they were not designed to allow

estimation of prevalence rates of symptoms or illnesses or to make scientific inferences about the

relationships between potential risk factors and illnesses. Similarly, most of the studies that have

been published concerning physical and psychological symptoms of various groups of Gulf War

veterans have missing or inadequate comparison groups, inadequate participant sampling methods,

andpoor participation rates that make scientific inferences hazardous at best (e.g., Haley et al., 1997;

Haley & Kurt, 1997; Ross & Wonders, 1993).

There has been one well-designed and well-conducted population-based study of self-reported

symptoms and exposures among Gulf War veterans (Iowa Study Group, 1997). Fortunately, the

findings with respect to self-reported symptoms of this study are very consistent many other studies

that are potentially biased. That is, in this study of 3695 Gulf War veterans, those who were

deployed to the Gulf (relative to those than not deployed to the Gulf) reported more symptoms of

depression (17% vs. 11%), PTSD (1.9% vs. 0.8%), chronic fatigue (1.3% vs. 0.3%), cognitive

dysfunction (18.7% vs. 7.6%), bronchitis (3.7% vs. 2.7%), asthma (7.2% vs. 4.1%), fibromyalgia

(19.2% vs. 9.6%), alcohol abuse (17.4% vs. 12.6%), anxiety (4.0% vs. 1.8%), and sexual discomfort

(1.5% vs. 1.0%). It was also observed that the National Guard / Reserve group reported, in general,

more symptoms than the regular military group. Interestingly, 83% of the regular military group and

96% of the National Guard / Reserve group reported exposure to psychological stressors.

Page 45

Report of the Special Investigation Unit on Gulf War Illnesses

201

This well-conducted study can provide an illustration of why post-event self-reported exposures

are poor indicators of exposure in studies of this type. Virtually all of the self-reported symptom

outcomes were each related to several of the exposure risk factors (e.g., solvents, smoke, infectious

agents). Of the three outcomes reported in some detail (self-reported symptoms of depression,

cognitive dysfunction, and fibromyalgia) for participants who were deployed to the Gulf, all three

showed statistically significant prevalence differences between exposure risk groups based on each

of at least eight different exposures. For all three of these outcomes (surprisingly) “ionizing/non-

ionizing radiation” was the exposure risk having the largest prevalence difference, i.e., greater than

that for solvents, lead, infectious agents, pesticides, chemical warfare agents, or pyridostigmine use.

Few environmental health scientists would predict that the relationships between radiation and these

threeoutcomes should be the strongest observed or would claim that they were biologically plausible.

It seems likely that reporting biases created these relationships. (It should be noted that the authors

of the paper did not emphasize or misinterpreted these findings. They are used here only to illustrate

thehazards of interpreting relationships between self-reported exposures and outcomes based on self-

report.)

Virtually all of the other studies of symptoms of Gulf War veterans have been conducted on

samplesthat have participant (self-) selection bias so substantial that no valid inferences can be made

from the data collected as to likely effects of environmental exposures in the Gulf War veteran

population. Moreover, even when such sampling biases are well controlled, as in the Iowa study, if

boththe potential exposures and the outcomes (physical and psychological symptoms) are measured

bymeans of self-report, no scientifically definitive conclusions concerning the potential relationships

between these variables can be performed. Not only are both sets of measures subject to potential

reporting biases, but the reporting biases will tend to be correlated, which will introduce artifactual

relationships between the two sets of measurements (Cohen, Kessler & Gordon, 1995). Only in

studiesin which both the exposures and the outcomes are measured objectively on population-based

samples with high participation rates will scientifically defensible inferences about relationships

between those exposures and outcomes be possible.

HOW IS STRESS LIKELY TO AFFECT OUTCOMES IN HEALTH STUDIES?

tress may have a negative impact on health research outcomes via at least four mechanisms:

! A direct effect on physical disease outcomes, e.g., chronic heart disease.

! A direct cause of psychopathology, e.g., PTSD or somatization disorder.

! Modulation of physiological action of infectious agents or inflammatory processes, e.g.,

increased susceptibility to infection.

! Modulationof the reporting of symptoms, e.g., changing the threshold for complaining about

discomfort, the rating of intensity of discomfort, or considering discomfort debilitating.

Page 46

United States Senate Committee on Veterans’ Affairs

202

There is no evidence that stressors in the Gulf War had a direct effect on physical disease

outcomes. There have been diagnosed cases of PTSD that, by definition, would be evidence of the

second mechanism, although the number of such diagnosed cases may not be large. Several studies

of“symptoms of PTSD” might provide evidence of the second mechanism, if there the stress exposure

measurements were assumed to be valid and sampling of participants were adequate. No studies of

infectious agents or inflammatory processes among Gulf War veterans are available that relate those

outcomes to stress exposures. No studies have been reported that address the fourth potential

mechanism, and it is difficult to determine how to test it empirically. It would, at a minimum, require

pre-deployment data on individuals trait negative affect (Watson & Pennebaker, 1989; Costa &

McCrae, 1987). However, this mechanism is plausible, and if individuals with high negative affect

volunteered to participate in the research studies than individuals with lower negative affect, it could

account for many observed findings of increased reporting of a wide range of symptoms.

HOW CAN WE KNOW WHETHER STRESS IS CONTRIBUTING FACTOR

TO SYMPTOMS REPORTED BY GULF WAR VETERANS?

e can’t. It is not possible to test directly whether symptoms reported by Gulf War veterans are

due to combinations of significant stressors that they experienced because retrospective

reporting biases in assessing both exposures and symptoms cannot now be overcome.

However, we can evaluate whether data already collected on Gulf War veterans are consistent

with predictions that we would make if we assume that the reported symptoms of many Gulf War

veterans are due to exposure to significant non-toxic physical and psychological stressors. One

would predict (A) that military personnel that were better inoculated against the potential effects

of the physical and psychological stressors of Gulf War combat (e.g., active duty soldiers) would

report fewer or less intense symptoms than those less well inoculated (e.g., reserve duty soldiers),

assuming that the level of stressors experienced by the two groups were comparable. One would

expect (B) that any new illness or discomfort would be more likely to be reported among those

experiencing a recent significant set of stressors (i.e., Gulf War deployment) than among those not

experiencing such intense stressors (e.g., deployment to Europe) or any new stressors (e.g., not

deployed). One would predict (C) that military personnel experiencing conditions associated with

substantial psychological distress after deployment, e.g., divorce or death in the family, would report

more symptoms than those not having such experiences post-deployment. One would predict (D)

that, relative to military personnel with poor social support at home, soldiers with better social

support at home would report more acute symptoms in the Gulf War theatre (a weak prediction),

but would report fewer symptoms after returning home (a stronger prediction). One would predict

(E) that individuals having a history of childhood trauma or minor psychological trauma before

deployment would report more symptoms after deployment than those without such a history.

Evidence consistent with some of these predictions is available in reports of studies of Gulf War

veterans, e.g., predictions A and B are supported by data in the Iowa Study (Iowa Study Group,

Page 47

Report of the Special Investigation Unit on Gulf War Illnesses

203

1997). Further, it may be possible to test some of these predictions (e.g., predictions C, D, and E)

by performing additional analyses of data already collected on Gulf War veterans.

CONCLUSION

neshould notread this report and come to the conclusion that it implies that the symptoms that

many Gulf War military personnel have reported are simply “in their head”. In truth, I do not

know why so many Gulf War veterans are reporting symptoms, and the literature does not support

mehaving a scientifically based opinion. I assume that some are experiencing conditions and disease

processes that would have happened without deployment to the Gulf War. My honest conclusion

is that it is quite plausible that exposure to physical and psychological stressors has exacerbated

physical conditions already present in some, exacerbated psychological conditions present in some,

and has decreased the threshold for complaining about ailments in some. I can think of no exposure

other than the wide range of potent stressors that would have potential effects on the reporting of

so many different types of symptoms.

DOD and the VA are currently funding several ongoing studies concerning stress symptoms.

Unless they are population-based, the participation rates are high, and the exposures are measured

objectively, they are unlikely to yield useful information about relationships between Gulf War

exposures and subsequent symptoms.

The fact that most people exposed to even substantial stressors do not develop symptoms (even

when a substantial number do) suggests that personal vulnerability factors may be involved.

Therefore, it would seem prudent to investigate which factors might be protective for, and which

factors may place individuals at risk for, experiencing symptoms following combat deployment.

RECOMMENDATIONS

ollow the PAC’s recommendations on peer-review of research proposals and establishing external

scientificadvisory panels for large projects. The Gulf War veteran literature is loaded with papers

describing studies with methodological flaws that weaken their generalizability, and in many cases

their validity. Perhaps there would be fewer if all proposals had been subjected to rigorous peer

review and the conduct of the studies were subjected to periodic scientific review.

Minimize the number of studies that do not have both objective exposure information and

objectivehealth outcome information. (This will probably follow if #1 is observed.) Studies relating

self-reportedexposures to self-reported symptoms or other measures derived from self-reports are not

scientifically interpretable. Perhaps improved record-keeping of the locations of military personnel

will help in developing objective exposure measures, and perhaps improved medical record-keeping

of objective findings from medical tests will help provide objective health outcome measures. In

Page 48

United States Senate Committee on Veterans’ Affairs

204

addition, improved automated techniques for acquiring health-related physiological and behavioral

data might prove useful.

Fund research projects aimed at the identification of personal risk factors for the development

of stress-related psychological and physical illness. For example, collect baseline data on “trait

negative affect” on all individuals who may be sent into combat and perform prospective studies of

howwell measures of this construct predict subsequent complaints, actual disease, and use of medical

services. Acquire baseline information on history of traumatic exposures, alcohol/substance abuse,

etc.

Formally evaluate the effectiveness of combat stress prevention programs, e.g., the U.S. Army’s

CombatStress Control Detachments, and expand them if they are found to be effective in minimizing

combat and post-combat stress. What information or training prior to deployment can best

“innoculate”military personnel to withstand better the whole range of combat deployment stressors?

What information or procedures might improve the coping skills of military personnel post-

deployment?

REFERENCES

Amato AA, McVey A, Cha C, Matthews EC, Jackson CE, Kleingunther R, Worley L,

Cornman E, and Kagan-Hallet K. Evaluationof neuromuscular symptoms in veterans of the

Persian Gulf War. Neurology 47: 4-12, 1997.

APA. Diagnostic and Statistical Manual of Mental Disorders (4

Edition). Washington DC:

American Psychiatric Association, 1994.

Baum A, Gatchel RJ, and Schaeffer MA. Emotional, behavioral, and physiological effects of

chronic stress at Three Mile Island. Journal of Consulting and Clinical Psychology 51: 565-

572, 1983.

Bromet E and Dew MA. Review of psychiatric epidemiologic research on disasters.

Epidemiologic Reviews 17: 113-119, 1995.

Chrousos GP and Gold PW. The concepts of stress and stress system disorders: Overview of

physical and behavioral homeostasis. JAMA 297: 1244-1252, 1992.

Cohen S, Kessler RC, and Gordon LU. Measuring stress: A guide for health and social

scientists. New York: Oxford University Press, 1995.

CostaPT Jr., and McCrae RR. Neuroticism, somatic complaints, and disease: Is the bark worse

than the bite? Journal of Personality 55: 299-316, 1987.

Page 49

Report of the Special Investigation Unit on Gulf War Illnesses

205

DayalHH, Baranowski T, Li Y, and Morris R. Hazardous chemicals: psychological dimensions

of the health sequelae of a community exposure in Texas. Journal of Epidemiology and

Community Health 48: 560-568, 1994.

Gal R and Jones FD. A psychological model of combat stress. Textbook of Military Medicine:

War Psychiatry. Falls Church, Va.: Office of the Surgeon General, 1995.

10. Goldstein G, Beers SR, Morrow LA, Shemansky WJ, and Steinhauer SR. A preliminary

neuropsychological study of Persian Gulf veterans. Journal of the International

Neuropsychological Society 2: 368-371, 1996.

11. Gray GC, Coate BD, Anderson CM, Kang HK, Berg SW, Wignall FS, Knoke JD, and Barrett-

Connor E. The postwar hospitalization experience of U.S. veterans of the Persian Gulf War.

New England Journal of Medicine 335: 1505-1513, 1996.

12. Haley RW. Is Gulf War Syndrome due to stress? The evidence revisited. American Journal

of Epidemiology 146: 695-703, 1997.

13. Haley RW, Kurt TL, and Hom J. Is there a Gulf War syndrome? Searching for syndromes by

factoranalysis of symptoms. Journal of the American Medical Association 277: 215-222, 1997.

14. Haley RW, Hom J, Roland PS, et al. Evaluation of neurologic function in Gulf War veterans:

a blinded case-control study. Journal of the American Medical Association 277: 223-230,

1997.

15. Haley RW and Kurt TL. Self-reported exposure to neurotoxic chemical combinations in the

GulfWar: a cross-sectional epidemiologic study. Journal of the American Medical Association

277: 231-238, 1997.

16. Herbert TB and Cohen S. Stress and immunity in humans. Psychosomatic Medicine 55: 394-

379, 1993.

17. Hyams KC, Wignal FS, and Roswell R. War syndromes and their evaluation: From the U.S.

Civil War to the Persian Gulf War. Annals of Internal Medicine 125: 398-405, 1996.

18. Iowa Persian Gulf Study Group. Self-reported illness and health status among Gulf War

veterans. Journal of the American Medical Association 277: 238-245, 1997.

19. Jones FD. Psychiatric lessons of war. Textbook of Military Medicine: War Psychiatry. Falls

Church, Va.: Office of the Surgeon General, 1995.

Page 50

United States Senate Committee on Veterans’ Affairs

206

20. Kang HK and Bullman TA. Mortality among U.S. veterans of the Persian Gulf War. New

England Journal of Medicine 335: 1498-1504, 1996.

21. Kiecolt-GlaserJK and Glaser R. Psychoneuroimmunology and health consequences: Data and

shared mechanisms. Psychosomatic Medicine 1995, 57: 299-274, 1995.

22. Lerman C and Glanz K. Stress, coping, and health behavior. In Glanz, Lewis & Rimer (eds.)

Health Behavior and Health Education 2

Ed. San Francisco: Josey-Bass, 1997, pp.113-138.

23. Lopez-Ibor JJ Jr., Soria J, Canas F, Rodriguez-Gamazo M. Psychopathological aspects of the

Toxic Oil Syndrome catastrophe. British Journal of Psychiatry 147: 352-265, 1985.

24. Newmark J and Clayton WL. Persian Gulf illnesses: Preliminary neurological impressions.

Military Medicine 150: 505-507, 1995.

25. PAC. Final Report of the Presidential Advisory Committee on Gulf War Veterans’ Illnesses.

Washington, D.C.: U.S. Government Printing Office, 1996.

26. Pennebaker JW. The psychology of physical symptoms. New York: Springer-Verlag, 1982.

27. Pennebaker JW. Psychological bases of symptom reporting: Perceptual and emotional aspects

of chemical sensitivity. Toxicology and Industrial Health, 10: 497-511, 1994.

28. PerconteST, Wilson AT, Pontius EB, Dietrick AL, and Spiro KJ. Psychological and war stress

symptoms among deployed and non-deployed reservists following the Persian Gulf War.

Military Medicine 158: 516-521, 1993.

29. Robbins JM and Kirmayer LJ. Cognitive and social factors in somatization. In: Kirmayer LJ

& Robbins JM (eds.) Current Concepts of Somatization, 1991, pp.107-142.

30. Ross MC and Wonders J. An exploration of the characteristics of post-traumatic stress

disorder in reserve forces edployed during Desert Storm. Archives of Psychiatric Nursing 5:

265-269, 1993.

31. Sloan P, Arsenault L, Hilsenroth M, and Harvill, L. Use of the Mississippi Scale for combat-

related PTSD in detecting war-related, non-combat stress symptomatology. Journal of Clinical

Psychology 51: 799-801, 1995.

32. Stretch RH, Bliese PD, Marlowe DH, Wright KM, Knudson KH, and Hoover CH. Physical

health symptomatology of Gulf War-era service personnel from the states of Pennsylvania and

Hawaii. Military Medicine 160: 131-136, 1995.

Page 51

Report of the Special Investigation Unit on Gulf War Illnesses

207

33. Stretch RH, Bliese PD, Marlowe DH, Wright KM, Knudson KH, and Hoover CH.

Psychological health of Gulf War-era military personnel. Military Medicine 161: 257-261,

1996.

34. Sutker PB, Uddo M, Brailey K, and Allain AN Jr. War-zone trauma and stress-related

symptoms in Operation Desert Shield/Storm (ODS) returnees. Journal of Social Issues 4: 33-

49, 1993.

35. Watson D and Pennebaker JW. Health complaints, stress, and distress: Exploring the central

role of negative affectivity. Psychological Review 96: 234-254, 1989.

36. Wolfe J, Brown PJ, and Kelley JM. Reassessing war stress: Exposure and the Persian Gulf War.

Journal of Social Issues 4: 15-31, 1993.

Page 52

United States Senate Committee on Veterans’ Affairs

208

AIR POLLUTANT EXPOSURE AND POTENTIAL HEALTH

EFFECTS AMONG PERSIAN GULF WAR VETERANS

Prepared by: Michael Lebowitz, Ph.D., Professor of Medicine, Pulmonary and Critical Care

Medicine; Professor and Director of Epidemiology, Arizona Prevention Center; Chair,

Epidemiology Graduate Interdisciplinary Program, University of Arizona, Tucson

SUMMARY

XPOSURES

The Persian Gulf War was associated with increased air pollution problems in some military

operations areas occupied by U.S. personnel, and in some urban areas in Kuwait and Saudi Arabia.

These problems included: i) occasional increased smoke from oil well fires (and some from use of

unvented kerosene heaters in enclosed spaces); ii) some short-term increases in typical combustion

gases (sulfur oxides -SOx, and nitrogen oxides - NOx) from oil well fires (and NOx from increased

vehicular exhaust in some areas); and iii) some increases in Volatile Organic Compounds (VOCs)

related to oil well fires, increased vehicular exhaust (mostly in non-urban areas), vehicle-related

activities (including sand suppression) by troops, and (it is estimated) from the use of unvented

kerosene heaters.

These increases in air pollution were primarily localized to areas of military activity and areas

downwind from the fires (when the plumes turned from prevailing—westerly and easterly—to

southerly directions, which was not very frequent). The increases in particulate matter (PM) were

incremental to existing high sand-related particulate matter (PM) found in these areas (a large

proportion of which are fine particles). Some VOC and NOx emissions increased in the region after

the war with a return to industrial activities and vehicular traffic in urban areas. (These exposures

were in addition to those normally experienced by deployed personnel in the theater of operations,

andthus included exposures to some reasonably high levels of bacillus species, pollen, fungal spores.)

(A Glossary of terms is at the end of the full report in the Appendix.)

OTENTIAL

EALTH

FFECTS

It can be assumed that some acute effects occurred, based on increased levels of particulate matter

and irritant gases associated with the war [e.g., diesel and turbine engine fumes, kerosene heater

exhaust, artillery-related smoke, etc.]. Respiratory problems (thought not to be related to

oil-well-fire pollution) were reported by U.S. troops and DOD civilian contractors, (some of whom

Page 53

Report of the Special Investigation Unit on Gulf War Illnesses

209

had pre-existing cardiopulmonary disease and may also have been smokers), and resident civilians.

Sick call for respiratory complaints among U.S. military personnel comprised 19% of all sick calls,

compared to a sick call rate of 7% for military personnel stationed in the States. Other potentially

relevant complaints (including gastro-intestinal (GI), eye, and neuropsychological symptoms), as

possibly related to air pollution exposures, were said to increase in the U.S. personnel . Information

on other foreign personnel and Persian Gulf troops is limited. However, a British prospective study

of 125 troops reported no significant change in lung function due to deployment in Kuwait (cf

Reference 15), though this may be questioned. Further studies continue.

A Kuwaiti study reported significant increases in respiratory illnesses in the residential area of

Kuwait City (cf Reference 16). In their high-risk residential populations asthma admissions to

hospital did not increase immediately, but admissions for chronic obstructive pulmonary diseases

(COPD: bronchitis, emphysema, bronchiectasis) did (Jan.-April 1991). They also saw increases for

GI illnesses, heart disease, and psychiatric complaints. [A surveillance system was organized, and an

attempt was made to create a longitudinal study of exposed and asthmatics, (by a CDC medical

epidemiologist) in Kuwait city, but it appears not to have come off.] Current status of residents is not

really known, though some increase in asthma was reported to a visitor. It is unlikely that the

temporary increases in air pollutants due to the war and its aftermath (including the oil well fires)

will have a major long-term effect in civilian, resident populations, though some individuals may

have been affected. An alert system and preventive education for physicians & civilians was also

attempted; implementation appears not to have occurred. These attempts should be evaluated

further before new studies are suggested, designed, or implemented in the civilian population of the

affected countries.

One major problem emerged, that of desert sand pneumonitis, a prolonged respiratory

inflammatory process (often with some fibrosis & lung destruction), at least in U.S. and British

troops. This pneumonitis is currently thought to be related to inhalation of fine sand by previously

unexposed individuals. Other exposures were thought to act as adjuvants, and the pneumonitis

produced was thought to affect the immune system (which will be discussed further). An autopsy

study (of troops) also revealed what the pathologist called obstructive bronchitis and bronchiolitis,

as well as sand particles. The sand also produced opthalmalogic (eye) problems. Thus, for some

newly-exposed individuals, some long-term problems, immunologic or respiratory, may have been

created. Further, it is unknown presently what effects pre-conditions (including prior treatments in

the military) and other possible exposures (e.g., exposure to chemical/biological warfare [CBW]

agents) may have had in foreign personnel, acutely or chronically, alone or in combination. Some

on-going studies are addressing these questions. These results should be evaluated further before

some of the specific studies are implemented in the U.S. personnel who served in the Persian Gulf.

However, a better review of records and further evaluation of those who served is warranted.

Page 54

United States Senate Committee on Veterans’ Affairs

210

RECOMMENDATIONS

Record searches in the DoD and VA Registries and in the VA healthcare system should be

made to determine if deployed personnel are experiencing more respiratory problems.

It should be determined if there have been more respiratory diseases reported in civilians in

Kuwait, and, if so, what kind of diseases.

An epidemiological study should be performed of respiratory and other toxic endpoints

associated with specific air pollutants indicated to be of concern. It can be performed in

deployed and non-deployed personnel using appropriate physiological, immunological and

techniques, biomarkers of effects, and epidemiological questionnaires (including location of

deployment and exposure information).

Further studies of absorption, inhalation and ingestion of volatile organic and similar

compounds used in the Desert Shield/Desert Storm theater of operations should be performed

in controlled human exposure studies, using exposures at the maximum concentrations

estimated for each of these pollutants. Physiological, immunological and neurological studies

should be performed in these experiments.

Further inhalation toxicological studies should be performed using reasonable concentrations

of mixtures of fine particles/diesel fumes with specific metals, and with some of the VOCs

detected in the Gulf.

The DVA should start a more complete registry of all Gulf-deployed personnel seen in the VA

system, with follow-up of 20 years, as a valuable determinant of long-term effects. Their rates

of illness and death could be compared to similar aged U.S. residents. It would be of great

benefit also if clinical work-ups of these personnel were standardized and included appropriate

techniques for the various long-term effects expected (e.g., respiratory diseases, neurological

diseases, cancer). The recommendations stemming from the IOM and PAC panels are also

worthwhile.

REFERENCES

El-Shobokshy MS, et al. “Inhalable Particulates and Meteorological Characteristics of the City

of Riyadh, Saudi Arabia.” Atmospheric Environment, Vol. 24B, No. 2 261-265, 1990.

Al-Frayh A, et al. “A 12-Month Aerobiological Survey of Pollen in Riyadh.” Annals of Saudi

Medicine, Vol. 9 No. 5, 443-447, 1989.

Page 55

Report of the Special Investigation Unit on Gulf War Illnesses

211

Hasnain SM, et al. “Seasonal Periodicities of Fungal Allergens in the Atmosphere of Riyadh.”

Annals of Saudi Medicine, Vol. 9, No. 4, 337-343, 1989.

Al-Frayh A, et al. “Fungal Allergens in the Atmosphere of Riyadh: A Preliminary

Communication.” Annals of Saudi Medicine, Vol. 8, No. 4, 248-251, 1988.

al-Nahdi M, et al. “An Aerobiological Survey of Allergens in al Khobar, Saudi Arabia.”

Allergie et Immunologie, 21 (7): 278-82, September 1989.

Hasnain SM, et al. “Airborne and Allergenic Fungal Spores at Various Sites in Saudi Arabia.”

4th International Conference on Aerobiology, Abstracts, August 27-31, 1990.

Halwagy M. “Airborne Pollen Calendar of Kuwait, 1975-1987.” 4th International Conference

on Aerobiology, Abstracts, August 27-31, 1990.

Marafie MRH, et al. “Airborne Bacteria in Kuwait (1986-1988).” Grana 30: 472-476, 1991.

StevensR, et al. “Chemical and Physical Properties of Emissions from Kuwaiti Oil Fires.” Wat.

Sci. Tech. Vol. 27, No 7-8, 223-233, 1993.

Cofer WR III, et al. “Kuwaiti Oil Fires: Compositions of Source Smoke.” Journal of

Geophysical Research, Vol. 97, No. D13, 14.521-14.525, Sept. 20, 1992.

Lowenthal, et al. Geophysical Res. Letter 20: 691-93, 1993.

Hobbs PV and Radke LF. “Airborne Studies of the Smoke from the Kuwaiti Oil Fires.” Science

Vol. 256, 15 May, 1992.

Johnson DW, et al. “Airborne Observations of the Physical and Chemical Characteristics of

the Kuwait Oil Smoke Plume.” Nature, Vol. 353, 17 October 1991.

Laursen KK, et al. “Emission Factors for Particles, Elemental Carbon, and Trace Gases form

the Kuwait Oil Fires.” Journal of Geophysical Research Vol. 97, No. D13, 14,491-14,497,

September 20, 1992.

10. Ferek RJ, et al. “Chemical Composition of Emissions from the Kuwait Oil Fires.” American

Geophysical Union, 14, 483-14,489, 1992.

11. RaveendranE, et al. “Trace Metals in the Atmosphere of Bahrain during the Kuwait Oil Fires.”

Environmental Technology, Vol. 13, 1097-1100, 1992.

Page 56

United States Senate Committee on Veterans’ Affairs

212

Madany IM and Raveendran E. “Polycyclic Aromatic Hydrocarbons, Nickel and Vanadium in

Air Particulate Matter in Bahrain during the Burning of Oil Fields in Kuwait.” The Science of

the Total Environment, 116, 281-289, 1992.

12. Hunt WF Jr. “The Impact of the Kuwait Oil Fires - An Overview.” Air and Waste

ManagementAssociation, 85th Annual Meeting & Exhibition, Kansas City, MO., June 21-26,

1992.

13. Small RD. “Environmental Impact of Fires in Kuwait.” Nature, Vol. 350, 11-12, March 7,

1991.

14. Bakan S, et al. “Climate Response to Smoke from the Burning Oil Wells in Kuwait.” Nature,

Vol. 351, 367-371, 30 May 1991.

Flam F, editor. “A Brighter Forecast from Kuwait.” Briefings, Science, Vol. 253, 28-29, July

1991. Holden C. “Kuwait’s Unjust Deserts: Damage to its Desert.” News & Comment, 1175,

8 March 1991.

Hahn J. “Environmental Effects of the Kuwaiti Oil Fires.” Environ. Sci. Technol., Vol. 25, No.

9, 1530-1532, 1991.

Simons M. “British Study Disputes Lengthy Climatic Role for Kuwait Oil Fires.” New York

Times, Aril 16, 1991: C4.

15. Coombe Capt. MD. “Assessment of the Effects of Atmospheric Oil Pollution in Post War

Kuwait.” JR Army Med Corps, 139: 95-97, 1993.

16. Al-Yakoob SN, et al. “Exposure to Particle-Bound Polyaromatic Hydrocarbons in the

Al-Mansoria Residential Area during the Kuwait Oil Fires: A qualitative Appraisal of the

Adsorption Role.” Environmental International, Vol. 19, 319-331, 1993.

17. Browning KA, et al. “Environmental Effects from Burning Oil Wells in Kuwait.” Nature, Vol.

351, 363-367, 30 May 1991.

18. Khattak MN. “Natural and Anthropogenic Atmospheric Particulates at UPM Campus,

Dhahran, Saudi Arabia.” Journal of the Air Pollution Control Association, Vol. 32, No. 11,

1153-1155, 1982.

19. Nasralla MM. “Air Pollution in the Semitropical Saudi Urban Area.” Environmental

International, Vol. 9, 255-264, 1993.

Page 57

Report of the Special Investigation Unit on Gulf War Illnesses

213

20. Rowe DR, et al. “Indoor-Outdoor Relationship of Suspended Particulate Matter in Riyadh,

Saudi Arabia.” Journal of the Air Pollution Control Association, Vol. 35, No. 1, 24-26, 1985.

21. RoweDR, et al. “Indoor-Outdoor Nitric Oxide and Nitrogen Dioxide Concentrations at Three

Sites in Riyadh, Saudi Arabia.” J. Air Waste Manage. Assoc., Vol. 41, No. 7, 973-976, July

1991.

22. MoschandreasD and Relwani S. “Emission Rates from Unvented Appliances.” Environmental

International, Vol. 12, 247-253, 1996.

23. Leaderer BP, et al. “Assessment of Exposure to Indoor Air Contaminants from Combustion

Sources: Methodology and Application.” Am J. Epidemiology, 124:275-89, 1986.

24. Darcey D J, et al. “DNA Adducts and Exposure to Burning Oil.” The Lancet, Vol. 339, 489,

February 22, 1992.

25. Riley JJ, et al. “Effect of Kuwait Oil Fires on Human Comfort and Environment in Jubail, Saudi

Arabia.” Int. J. Biometeorol. 36: 36-38, 1992.

26. Korenyi-Both, AL. “Al Eskan Disease: Persian Gulf Syndrome.” Military Medicine, Vol. 162,

1: 001, 1-13, 1997.

27. Irey NS. “Kuwait Casualties: Morphological and Toxicologic Findings. The Persian Gulf

Experience and Health.” NIH Technology Assessment Statement, April 27-29, 1994.

28. Hawass ND. “An Association between “Desert Lung” and Cataract - A New Syndrome.” Br

J Ophthamol 71:694-7, 1986.

29. Richards AL, et al. “Respiratory Disease among Military Personnel in Saudi Arabia during

Operation Desert Shield.” American Journal of Public Health, Vol. 83, No. 9, 1326-1329,

1993.

30. Jedrychowski W, et al. “Height and Lung Function in Preadolescent Children of Kuwaitis and

European Origin: A Pilot Survey on Health Effects of Gas Cooking in the Middle East.”

Archives of Environmental Health, Vol. 46, No. 6, 361-365, 1991.

31. Abou-Donia MB and Kenneth R. Wilmarth. “Neurotoxicity Resulting form Coexposure to

Pyridostigmine Bromide, Deet, and Permethrin: Implications of Gulf War Chemical

Exposures.” Journal of Toxicology and Environmental Health, 48: 35-56, 1996.

Page 58

United States Senate Committee on Veterans’ Affairs

214

32. Ainslie G. “Inhalation Injuries Produced by Smoke and Nitrogen Dioxide.” Respiratory

Medicine, Vol. 87, 169-174, 1993.

Baker CDR. MS, et al. “Medical Aspects of Persian Gulf Operations: Serious Infectious and

CommunicableDiseases of the Persian Gulf and Saudi Arabian Peninsula.” Military Medicine,

Vol. 156, 385-390, August 1991.

33. Bizovi KE and Leikin JD. “Smoke Inhalation among Firefighters.” Occupational Medicine:

State of Art Reviews, Vol. 10, No. 4, 721-733, Oct.- Dec. 1995.

34. Abbey DE, et al. “Chronic Respiratory Symptoms Associated with Estimated Long-term

Ambient Concentration of Fine Particulates less than 2.5 Microns in Aerodynamic Diameter

(PM2.5) and Other Air Pollutants.” Journal of Exposure Analysis and Environmental

Epidemiology, Vol. 5, No. 2, 137-159, 1995.

Euler GL, et al. “Chronic Obstructive Pulmonary Disease Symptom Effects of Long-term

Cumulative Exposure to Ambient Levels of Total Suspended Particulates and Sulfur Dioxide

inCalifornia Seventh-Day Adventist Residents.” Arch. Environ. Health 42 (4): 213-222, 1987.

Greer JR, et al. “Asthma Related to Occupational and Ambient Air Pollutants in

Non-smokers.” J. Occup. Environ. Med. 35 (9): 909-915, 1993.

35. Detels R, et al. “The UCLA Population Studies of COPD: X. A Cohort Study Changes in

Respiratory Function Associated with Chronic Exposure to SOx, NOx, and Hydrocarbons.”

Am. J. Public Health, 81 (3): 350-359, 1991.

Ostro BD. “Associations between Morbidity and Alternative Measures of Particulate Matter.”

Risk Anal. 10: 421-427, 1990.

36. SchwartzJ. “Particulate Air Pollution and Chronic Respiratory Disease.” Environ. Res. 62:7-13,

1993.

37. LebowitzMD. “Epidemiological Studies of the Respiratory Effects of Air Pollution.” Eur Respir

J. 9:1029-54, 1996.

Lebowitz MD and Spinaci S. “Epidemiology of Asthma.” Eur. Respir. Rev. 3:415-23, 1993.

38. Evans JS, et al. “Cross Sectional Mortality Studies and Air Pollution Risk Assessment.”

Environmental International, Vol. 10, 55-83, 1984.

Page 59

Report of the Special Investigation Unit on Gulf War Illnesses

215

Pope CA, et al. “Particulate Air Pollution as a Predictor of Mortality in a Prospective Study of

U.S. Adults.” Am. J. Respir. Crit. Care Med., Vol. 151, 669-674, 1995.

39. Finkelstein JN, et al. “Particulate-Cell Interactions and Pulmonary Cytokine Expression.”

Environmental Health Perspectives, Vol. 105, Suppl. 5, 1179-1182, Sept. 1997.

40. Golden AL, et al. “The Risk of Cancer in Firefighters.” Occupational Medicine: State of the

Art Reviews, Vol. 10, No. 4, 803-820, Oct.-Dec., 1995.

41. KelseyKT, et al. “Genotoxicity to Human Cells Induced by Air Particulates Isolated during the

Kuwait Oil Fires.” Environmental Research 64, 18-25, 1994.

Page 60

United States Senate Committee on Veterans’ Affairs

216

MYCOPLASMA AND ILLNESS

Prepared by: Kevin Dybvig, Ph.D., Professor, Departments of Comparative Medicine and

Microbiology, University of Alabama at Birmingham

SUMMARY

lthough during the past 30 years the clinical significance of Mycoplasma fermentans has been

at times the center of controversy, most studies indicate that this organism should be considered

normal flora of the human genital tract and throat. The available data are insufficient to conclude

that M. fermentans is more prevalent in veterans of the Persian Gulf War than in the general

population. The only reports suggesting that M. fermentans may be more prevalent in Gulf War

veterans are the work of Drs. Garth and Nancy Nicolson. These unconfirmed reports are based on

the analysis of samples from a very small number of patients and are not technically rigorous.

Moreover, even if M. fermentans were found to be prevalent in Gulf War veterans, there is no reason

to believe this organism would be responsible for the unusual symptoms referred to collectively as

Gulf War Illness (GWI). Consequently, the possibility that M. fermentans is involved in the etiology

of GWI does not warrant serious consideration.

I. M. FERMENTANS AND HUMAN DISEASE - A HISTORICAL PERSPECTIVE

M. fermentans has never been generally accepted as a pathogen of humans or animals. This organism

is considered to be a member of the normal human flora. It is also a common contaminant of culture

systemsused to propagate cells in the laboratory. M.fermentanshas been at times suspected of causing

various diseases in humans and, therefore, the center of some controversy. Studies suggesting that

M. fermentans may be a human pathogen have often proven to be irreproducible, and whether this

organism is a significant cause of human disease remains unclear.

A. M. fermentans and arthritis

In the late 1960's it was suggested that M. fermentans was a cause of rheumatoid arthritis (RA)

(28).This suggestion stemmed from the isolation of organisms from the synovial fluid of symptomatic

patients but lost favor because of the inability of other laboratories to replicate the findings (2). As

is typical for mycoplasmas, the initial report describing the isolation of M. fermentans from synovial

fluid may well have in actuality been an example of mycoplasma contamination of the serum

component of the culture medium used to recover organisms. Recently, an association between M.

fermentans and RA has been re-investigated using ultrasensitive polymerase chain reaction (PCR)

methods. Although one laboratory reported finding M.fermentansDNA in synovial fluid from a large

number of patients with RA (26, 27), another laboratory in a very well controlled study found no M.

Page 61

Report of the Special Investigation Unit on Gulf War Illnesses

217

fermentansDNA in synovial fluid from either normal patients or patients with RA (11). It is generally

viewedthat RA is an autoimmune disease and that the involvement of M.fermentansis unlikely (30).

B. M. fermentans and cancer

In the 1960's, some clinical observations suggested an association between infections by

mycoplasmas and malignancies in humans (10). Introduction of mycoplasmas to cultures of baby

hamsterkidney cells was reported to induce cell transformation (19). M. fermentanswas isolated from

specimens of bone marrow chiefly obtained from leukemic patients (20) and shown to induce

leukemoid disease in mice (22). Studies such as these gave rise to speculation that infection by

mycoplasmas may induce malignant transformation in humans. However, the prevailing notion

throughout the 1970's and 1980's was that M. fermentanswas an opportunist. The reduced resistance

of the host that accompanied leukemic disease was thought to facilitate low-grade infection by the

mycoplasma. Interestingly, the possibility that persistent infection by M. fermentans may induce

malignant transformation is being re-examined in the 1990's. M. fermentans has been shown to

induce transformation of mouse embryo cells (29, 31). Mouse cells maintained in culture are very

different from a whole animal. It cannot be overly emphasized that the ability to transform mouse

cells in culture may have little relevance to malignancy in humans. The possibility that mycoplasma

infection might lead to malignancy in humans is very remote.

C. M. fermentans and AIDS

M. fermentans received little scientific attention during the late 1970's and early 1980's, but once

again returned as a focus for mycoplasma research in the late 1980's. What brought M. fermentans

to the forefront was most likely a laboratory error resulting from contamination of a cell culture

system with this organism. Dr. Shih Lo reportedly isolated a novel virus from patients with AIDS in

1986 (14). The virus was obtained by isolating DNA from AIDS patients and introducing the DNA

directly into a mouse cell line by a process known as transfection. The “transfected” cells produced

an infectious agent, the reportedly new virus. It was later determined that the infectious agent was

not a virus at all but was a mycoplasma, originally identified by Dr. Lo as a new species, M. incognitus,

and later correctly identified as M. fermentans (16, 24). For a variety of reasons, mycoplasma DNA

cannot possibly transfect mammalian cells. Mammalian cells and mycoplasmas possess very different

factors that regulate gene expression. The mycoplasmal promoters and ribosome binding sites that

serve as important signals for gene expression (transcription) and protein synthesis (translation)

would not be correctly recognized by mammalian cells (8). Also, mycoplasmas do not use the typical

“universal” genetic code. In most organisms including mammals, the codon TGA is a stop codon

signaling the end of protein synthesis. In mycoplasmas, TGA encodes the amino acid tryptophan.

Whenexpressed in other organisms, the TGA codons in the mycoplasma genes cause the production

of prematurely truncated proteins that are not functional (7). For these reasons, mammalian cells

cannot use mycoplasma DNA to synthesize mycoplasma proteins, and it is not possible that

“transfected” mouse cells produced mycoplasmas. The initial report describing the isolation of M.

Page 62

United States Senate Committee on Veterans’ Affairs

218

fermentans (the reputed novel virus) by transfection was clearly an error. The most logical

explanation was that M. fermentans was present as a contaminant in the cell culture system used for

the transfection experiments (9).

The erroneous report of isolation of a novel virus (later identified as M. fermentans) from AIDS

patients led investigators to examine additional patients for the presence of this infectious agent.

These studies provided clear evidence that about 10% of AIDS patients have detectable levels of M.

fermentans DNA in their blood (5). Generally, investigators assumed this finding was merely a

reflection of the fact that AIDS patients carry a high load of pathogenic and opportunistic

microorganisms because of their suppressed immune systems. However, some investigators, most

prominently Luc Montagnier (the discoverer of HIV), began studying the possibility that M.

fermentansmay be a cofactor stimulating the development of disease (AIDS) in HIV-positive patients

(4). However, various studies indicated a lack of an association between M. fermentansand the stage

of disease in HIV patients. Also, the incidence of M. fermentans in blood is the same (about 10%) in

bothHIV-positive and HIV-negative patients (12, 13). The conclusion from these studies and others

is that M. fermentans is most likely part of the normal flora and is not involved in the progression of

disease in HIV patients. Recently, Montagnier has conceded that HIV can cause AIDS in the

absence of other cofactors such as M. fermentans (1).

D. M. fermentans and respiratory disease

Although M. fermentans appears to be a part of the normal human flora, there have been rare

cases in which patients have died from respiratory failure from what may have been an infection by

M. fermentans. Six such cases were reported, once again from the laboratory of Dr. Lo, in 1989 and

three more in 1993 (15, 18). Unfortunately, confirmatory results from other laboratories have not

been reported. Whether infection by M. fermentans was the primary cause of death in these patients

isnot known. If infection by M.fermentanswas responsible for these deaths, an explanation is lacking

for why an organism that is usually associated with human normal flora would cause an invasive,

acute respiratory disease in these particular patients.

Dr. Lo’s laboratory also has reported that M. fermentans can cause fatal disease in nonhuman

primates (silvered leaf monkeys) (17). These experiments were performed using only four animals

and have not been repeated in any laboratory. Also, inoculation of a different primate (macaques)

with high doses of M. fermentans has thus far failed to produce disease (A. Blanchard, unpublished

data). However, macaques and monkeys are different animals, and it is conceivable that M.

fermentans might cause disease in one species of animal and not the other. Therefore, whether M.

fermentans is capable of causing disease in nonhuman primates is an issue that will require more

experimentation if it is to be resolved.

E. M. fermentans and AIDS-associated nephropathy

Page 63

Report of the Special Investigation Unit on Gulf War Illnesses

219

There has been one unconfirmed report, also from Dr. Lo’s laboratory, of an association between

M. fermentans and kidney disease in AIDS patients (3). The clinical diagnosis in these patients is

AIDS-associatednephropathy. If the renal complications in these patients truly result from infection

by M. fermentans, the logical conclusion would be that this organism is an opportunist capable of

causing disease in specific situations such as when the host has a weakened immune system as is in

AIDS patients.

F. Summary of M. fermentans and human disease

M. fermentans has at times been proposed to be a human pathogen causing a variety of different

diseases (arthritis, cancer, AIDS, respiratory and kidney disease). The supporting evidence for any

of these possibilities is scant at best, and this organism should still be considered part of the normal

human flora. However, some microbes that have been considered normal flora in the past have been

shown to be pathogenic. For example, Helicobacter pylori was for years considered to be non-

pathogenic but has recently been shown to be a cause of stomach ulcers. Also, microbes which are

considered normal flora can sometimes cause significant health problems in patients who are at risk

because of other factors such as a compromised immune system or tissues that have been damaged

from injury or infection with other pathogens. Infectious diseases are complicated and much is not

known. It is conceivable that M. fermentans will one day be a recognized human pathogen.

II. M. FERMENTANS AND GULF WAR ILLNESS

A. Prevalence of M. fermentans

Few studies have examined the prevalence of M. fermentans in the general population because

the organism is presumed to be normal flora. Most studies examining prevalence have focused on

patients with specific disease symptoms in an effort to determine whether an association existed

between presence of the organism and disease. These studies have involved small numbers of patients

and have lacked an adequate assessment of the prevalence of organisms in the general population.

Obviously, different studies reach different conclusions regarding the prevalence of M. fermentans

depending on the diagnostic methods, the patient populations, and the particular types of samples

that were examined.

One recent study reported the detection of M. fermentans in saliva from 40% (49 of 110) of

healthy adults (6). A problem with this unconfirmed study is that sensitive PCR methods were used

and the negative controls (samples known not to contain M. fermentans) were not convincing. The

experiments were designed to PCR amplify M.fermentansDNA from saliva, and the negative controls

were PCR reactions in which no test sample (saliva) was added. The authors evidently believed their

negative controls worked; they thought no PCR product was obtained. However, from a careful

examination of the photograph provided in the report, it appears that negative control samples may

in fact have yielded a low level of M. fermentans PCR product. This could only result from DNA

Page 64

United States Senate Committee on Veterans’ Affairs

220

contamination. If the negative controls give a positive PCR product (no matter how weak), the

report cannot be trusted. When very sensitive PCR methods are employed, it is critical to ensure that

samples are not accidentally contaminated with DNA prior to PCR analysis. Contamination of

samples that are subjected to PCR analysis is a common problem and is one reason why it is

important for other laboratories to independently verify findings. Therefore, the prevalence of M.

fermentans in saliva from healthy adults must be considered unknown until confirmation is obtained

fromother laboratories. Other studies are also likely flawed because of contamination of samples with

M. fermentans DNA prior to analysis. For example, a report describing the detection of M. fermentans

DNA from lymph nodes of AIDS patients is questionable (25).

Reports indicate that blood from about 10% of the population contains M. fermentans DNA, and

evena higher percentage of people may contain M.fermentansin the throat. A study from the Institut

Pasteur in France reported finding M. fermentans DNA in blood from 8% of HIV-negative blood

donors, 15% of HIV-negative patients from a sexually transmitted disease clinic, and 6% of HIV-

positivepatients (13). Another study from the United Kingdom reported finding M.fermentansDNA

in blood from 10% of HIV-positive patients and 9% of HIV-negative patients from a sexually

transmitteddisease clinic (12). This latter study also found M. fermentans DNA in throat swabs from

23% of HIV-positive patients and 20% of HIV-negative patients.

It appears that M. fermentans DNA is commonly detected (5-20% of patients or blood donors)

by PCR analysis of blood, throat, and possibly saliva samples. PCR is the most appropriate assay for

the screening large numbers of patient samples because the principle alternative, isolation of M.

fermentans organisms by culture, is usually difficult and unreliable. However, additional studies from

multiple laboratories are required to truly ascertain the prevalence of this organism.

B. Prevalence of M. fermentans in Gulf War veterans

Because most investigators consider M. fermentans to be normal human flora, it is surprising that

aneffort was made to screen samples from Gulf War veterans for the presence of this organism. Blood

samples from Gulf War veterans were analyzed by a technique developed by Drs. Garth and Nancy

Nicolson and referred to as Nucleoprotein Gene Tracking (NGT). NGT is a procedure in which

nucleoprotein is isolated from host cells, size fractionated on polyacrylamide gels, transferred to a

hybridization membrane, and probed with DNA sequences specific for M. fermentans. This method

is similar to commonly used Southern hybridization methods, except that nucleoprotein and not

purified DNA is analyzed. The stated rationale for using this method was that some DNA sequences

may be specifically trapped in nucleoprotein complexes (23). The claim was that sequences

complexed with nucleoprotein might be lost with conventional Southern procedures, but would be

detected using the NGT method. However, the NGT system is an inappropriate diagnostic method

for detection of M. fermentans. Even if M. fermentans cells were themselves present inside human

cells, the mycoplasma DNA would still reside inside the mycoplasma cell and not be complexed with

human nucleoprotein. A serious concern is that the efficacy of the NGT method has not been

Page 65

Report of the Special Investigation Unit on Gulf War Illnesses

221

established. The sensitivity of the method has not been established by spiking control samples with

known numbers of M. fermentans organisms. Similarly, the specificity of the method has not been

established by spiking control samples with known numbers of organisms from other species of

mycoplasma.

Using the NGT method, the Nicolsons reported finding M. fermentans DNA in 14 of 30 patients

(21). A major drawback with this report is the lack of supporting documentation. Almost no data

are shown in this publication or any other report published by the Nicolsons. There is only one

sample from one individual (a single lane from a single gel) in which a putative nucleoprotein

complex was actually shown to react with a M. fermentans-specific probe. The case history of this

particular individual was not described. Case history has been provided for some patients, but

photographs of the Gene Tracking data for these patients are not published. In the Nicolson study,

M. fermentans DNA was not detected in any of 21 healthy individuals used as controls. However, it

is premature to conclude that the incidence of M. fermentans in Gulf War veterans is higher or lower

than it is in the general population because the Nicolson findings have not been confirmed by other

laboratories. In addition to the uncertainty of the effectiveness of the NGT method, the number of

samples analyzed from Gulf War veterans is few (only 30).

As explained above, the NGT method is inappropriate for detection of M. fermentans in samples

from Gulf War veterans because M. fermentans DNA resides within the mycoplasma cell and would

not be present in the material assayed by this procedure, namely, host nucleoprotein. An indication

of the unreliability of this technique is evidenced by the Nicolsons’ finding of M. fermentans DNA

and HIV DNA sequences present in the same nucleoprotein complexes. Some regions of the HIV

genome were detected but not others, indicating that HIV in its entirety was absent. Based on this

finding, the Nicolsons concluded that HIV sequences may have been inserted into M. fermentans by

genetic engineering, with the engineered strain being released into the environment either

accidentally or intentionally. The reality is that genetic engineering of M. fermentans is not

technically feasible at the present time and certainly did not occur prior to the Gulf War. Methods

for genetic engineering have been established for a few species of mycoplasma but not for M.

fermentans (8). Also, viruses that infect humans and other animals cannot infect bacteria and

mycoplasmas. One reason for this is that bacteria lack the receptors the virus needs to attach to the

cell’s membrane. In the case of HIV, M. fermentans lacks the CD4 receptor. Therefore, HIV could

not enter the mycoplasma. Because the NGT method yielded an impossible result (M. fermentans

DNA complexed with HIV DNA), none of the data obtained using this method can be trusted.

Therefore, there are no valid data linking M. fermentans with GWI.

C. Could M. fermentans cause disease with symptoms similar to GWI?

Because M. fermentans is generally considered normal human flora, it is expected that most

individuals colonized by M. fermentans would be healthy and have no symptoms of disease. However,

as mentioned above, many microbes that are usually considered normal flora can be pathogenic if

Page 66

United States Senate Committee on Veterans’ Affairs

222

the patient is immunocompromised. Also, there is ample evidence that synergistic interactions can

occur when multiple infections are simultaneously occurring in an individual. Therefore, it is

conceivable that M. fermentans is normal human flora and yet rarely capable of causing disease

(although not demonstrated to date).

IfM.fermentanscan cause human disease, what would be the expected symptoms? Obviously, any

comments in this area are speculative. Many mycoplasma species are respiratory pathogens, and as

noted above, there is some evidence to suggest that M. fermentans may rarely be associated with

respiratory disease. Also, as noted above, M. fermentans DNA has been reportedly detected in 20%

of throat samples from HIV-positive and HIV-negative individuals. It certainly is conceivable that

M. fermentans may cause respiratory problems and sore throats in some individuals. During an active

infection, other symptoms such as fatigue and fever may be expected. These symptoms would most

likely be temporary, disappearing as the infection ran its course. Several species of mycoplasma can

cause arthritis in various animal hosts. It is, therefore, conceivable that M. fermentans could be

associated with joint pain in some individuals (but, this again becomes speculative).

Specific cases involving subjects who are Gulf War veterans and have tested positive for the

presence of M. fermentans DNA in blood samples have been reported by the Nicolsons. Most of these

individualsreportedly had an array of symptoms including skin rashes, vision problems, memory loss,

diarrhea, and sleep problems (21). None of these symptoms are associated with any known disease

caused by any species of mycoplasma. The possibility that M. fermentans is responsible for these

symptoms is too remote to be seriously considered based on the available scientific evidence.

FINAL COMMENTS

t is very common for individuals to come in contact with potentially dangerous microbial

pathogens. These microbes are usually cleared from the body in a short period of time and result

in no disease. Therefore, the mere presence of organisms, even if they are known human pathogens,

isnot necessarily a health concern. One factor to be considered is the site where organisms are found.

For example, a particular bacterium may be of no concern if located in the intestine but a significant

concern if found in the lung. Another factor is the overall health of the individual. A third factor is

the virulence of the particular strain of bacteria that is found. For example, some strains of

Escherichia coli would be considered normal flora of the human intestinal tract whereas other strains

would cause potentially significant problems such as severe diarrhea. Unfortunately, virtually nothing

is known about factors (if they exist) that may make one strain of mycoplasma more virulent than

another. Therefore, no test is available to determine whether an individual is colonized with a

particularly virulent strain. Lastly, the quantity of bacteria present in a patient is important. Often,

a strain of bacteria will not cause disease unless it is present in high numbers. This is a drawback to

most studies that use DNA detection to identify the presence of microbes in a host. M. fermentans

DNA may be detected in blood or other samples from a patient, but the quantity of organisms is

unknown. Because M. fermentans is apparently present in many healthy people, investigators are

Page 67

Report of the Special Investigation Unit on Gulf War Illnesses

223

skeptical about its pathogenic potential. However, the possibility that some strains of M. fermentans

may be especially virulent and cause disease in susceptible individuals who happen to come in

contact with a high number of such organisms cannot at this time be proven or disproven. Even an

intensive effort by many laboratories could not resolve this issue in a short period of time. It would

take years of research to determine whether M. fermentans is not simply normal flora but in fact a

pathogen, but such expenditures definitely are not justified by the evidence available.

REFERENCES

Balter, M. 1998. The twin icons of French AIDS research. Science 279:313.

Barile, M. F., H. Yoshida, and H. Roth. 1991. Rheumatoid arthritis: new findings on the failure

to isolate or detect mycoplasmas by multiple cultivation or serologic procedures and a review

of the literature. Rev. Infect. Dis. 13:571-582.

Bauer, F. A., D. J. Wear, P. Angritt, and S.-C. Lo. 1991. Mycoplasma fermentans (incognitus

strain) infection in the kidneys of patients with acquired immunodeficiency syndrome and

associated nephropathy. Human Pathology 22:63-69.

Blanchard, A., and L. Montagnier. 1994. AIDS-associated mycoplasmas. Annu. Rev.

Microbiol. 48:687-712.

Brenner, C., O. Neyrolles, and A. Blanchard. 1996. Mycoplasmas and HIV infection: from

epidemiology to their interaction with immune cells. Front. Biosci. 1:42-54.

Chingbingyong, M. I., and C. V. Hughes. 1996. Detection of Mycoplasma fermentans in human

saliva with a polymerase chain reaction-based assay. Arch. Oral Biol. 41:311-314.

Dybvig, K. 1990. Mycoplasmal genetics. Annu. Rev. Microbiol. 44:81-104.

Dybvig, K., and L. L. Voelker. 1996. Molecular biology of mycoplasmas. Annu. Rev. Microbiol.

50:25-57.

Hannan, P. C. T. 1997. Observations on the possible origin of Mycoplasma fermentans

incognitus strain based on antibiotic sensitivity tests. J. Antimicrob. Chemother. 39:25-30.

10. Hayflick, L., and H. Koprowski. 1965. Direct agar isolation of mycoplasmas from human

leukaemic bone marrow. Nature 205:713-714.

Page 68

United States Senate Committee on Veterans’ Affairs

224

11. Hoffman, R. W., F. X. O’Sullivan, K. R. Schafermeyer, T. L. Moore, D. Roussell, R. Watson-

McKown, M. F. Kim, and K. S. Wise. 1997. Mycoplasma infection and rheumatoid arthritis.

Arthritis Rheum. 40:1219-1228.

12. Katseni, V., C. B. Gilroy, B. K. Ryait, K. Ariyoshi, P. D. Bieniasz, J. N. Weber, and D. Taylor-

Robinson.1993. Mycoplasmafermentansin individuals seropositive and seronegative for HIV-1.

Lancet 341:271-273.

13. Kovacic, R., V. Launay, P. Tuppin, A. Lafeuillade, V. Feuillie, L. Montagnier, and O. Grau.

1996.Search for the presence of six Mycoplasma species in peripheral blood mononuclear cells

ofsubjects seropositive and seronegative for human immunodeficiency virus. J. Clin. Microbiol.

34:1808-1810.

14. 14. Lo, S.-C. 1986. Isolation and identification of a novel virus from patients with AIDS. Am.

J. Trop. Med. Hyg. 35:675-676.

15. 15. Lo, S.-C., M. S. Dawson, P. B. Newton, III, M. A. Sonoda, J. W.-K. Shih, W. F. Engler, R.

Y.-H. Wang, and D. J. Wear. 1989. Association of the virus-like infectious agent originally

reported in patients with AIDS with acute fatal disease in previously healthy non-AIDS

patients. Am. J. Trop. Med. Hyg. 41:364-376.

16. Lo, S.-C., J. W.-K. Shih, P. B. Newton, III, D. M. Wong, M. M. Hayes, J. R. Benish, D. J. Wear,

and R. Y.-H. Wang. 1989. Virus-like infectious agent (VLIA) is a novel pathogenic

mycoplasma: Mycoplasma incognitus. Am. J. Trop. Med. Hyg. 41:586-600.

17. Lo, S.-C., R. Y.-H. Wang, P. B. Newton, III, N.-Y. Yang, M. A. Sonoda, and J. W.-K. Shih.

1989.Fatal infection of silvered leaf monkeys with a virus-like infectious agent (VLIA) derived

from a patient with AIDS. Am. J. Trop. Med. Hyg. 40:399-408.

18. Lo, S.-C., D. J. Wear, S. L. Green, P. G. Jones, and J. F. Legier. 1993. Adult respiratory distress

syndrome with or without systemic disease associated with infections due to Mycoplasma

fermentans. Clin. Inf. Dis. 17(Suppl 1):S259-S263.

19. MacPherson, I., and W. Russell. 1966. Transformation in hamster cells mediated by

mycoplasmas. Nature 210:1343-1345.

20. Murphy, W. H., C. Bullis, I. J. Ertel, and C. J. D. Zarafonetis. 1970. Isolation of mycoplasma

from leukemic and nonleukemic patients. J. Natl. Cancer Inst. 45:243-251.

21. Nicolson, G., and N. L. Nicolson. 1996. Diagnosis and treatment of mycoplasmal infections in

Persian Gulf War Illness-CFIDS patients. Int. J. Occup. Med. Immunol. Toxicol. 5:69-78.

Page 69

Report of the Special Investigation Unit on Gulf War Illnesses

225

22. Plata, E. J., M. R. Abell, and W. H. Murphy. 1973. Induction of leukemoid disease in mice by

Mycoplasma fermentans. J. Infect. Dis. 128:588-597.

23. Rosenberg-Nicolson, N. L., and G. L. Nicolson. 1994. Isolation, purification, and analysis of

specific gene-containing nucleoproteins and nucleoprotein complexes. Methods Mol. Genet.

5:281-298.

24. Saillard, C., P. Carle, J. M. Bove, C. Bebear, S.-C. Lo, J. W.-K. Shih, R. Y.-H. Wang, D. L.

Rose, and J. G. Tully. 1990. Genetic and serologic relatedness between Mycoplasma fermentans

strains and a mycoplasma recently identified in tissues of AIDS and non-AIDS patients. Res.

Virol. 141:385-395.

25. Sasaki, Y., M. Honda, M. Naitou, and T. Saski. 1994. Detection of Mycoplasma fermentans

DNA from lymph nodes of acquired immunodeficiency syndrome patients. Microb. Pathogen.

17:131-135.

26. Schaeverbeke, T., C. B. Gilroy, C. Bebear, J. Dehais, and D. Taylor-Robinson. 1996.

Mycoplasma fermentans in joints of patients with rheumatoid arthritis and other joint disorders.

Lancet 347:1418.

27. Schaeverbeke, T., C. B. Gilroy, C. Bebear, J. Dehais, and D. Taylor-Robinson. 1996.

Mycoplasma fermentans,but not M.penetrans,detected by PCR assays in synovium from patients

with rheumatoid arthritis and other rheumatic disorders. J. Clin. Pathol. 49:824-828.

28. Somerson, N. L., and B. C. Cole. 1979. The mycoplasma flora of human and nonhuman

primates, p. 191-216. In J. G. Tully and R. F. Whitcomb (ed.), The Mycoplasmas. Academic

Press, New York.

29. Tsai, S., D. J. Wear, J. W.-K. Shih, and S.-C. Lo. 1995. Mycoplasmas and oncogenesis:

persistent infection and multistage malignant transformation. Proc. Natl. Acad. Sci. USA

92:10197-10201.

30. Weyland, C. M., and J. J. Goronzy. 1997. Pathogenesis of rheumatoid arthritis. Adv.

Rheumatol. 81:29-55.

31. Zhang, B., J. W.-K. Shih, D. J. Wear, S. Tsai, and S.-C. Lo. 1997. High-level expression of H-

ras and c-myc oncogenes in mycoplasma-mediated malignant cell transformation. Proc. Soc.

Exp. Biol. Med. 214:359-366.

Page 70

United States Senate Committee on Veterans’ Affairs

226

EPIDEMIOLOGICAL STUDIES OF THE REPRODUCTIVE

HEALTH OF PERSIAN GULF WAR VETERANS

Prepared by: Shanna Swan, Ph.D., Chief, Reproductive Epidemiology Section, California

Department of Health Services

INTRODUCTION

his report reviews the epidemiologic studies that have been, and are being, conducted to assess

the reproductive health of personnel that served in the 1990-91 Persian Gulf War (PGW). To

thisend, I have attempted to review all relevant published studies, as well as proposals, protocols, and

questionnaires for ongoing studies. I have included all studies whose results were published in

scientific journals or presented at scientific meetings as of December 1, 1997, as well as studies that

were in progress as of that date.

With a few notable exceptions (e.g. the Oregon Health Sciences University study, and the

Klemm Analysis Group Study), the completed and ongoing studies are severely limited by their

incomplete exposure assessment. Because PGW veterans were potentially exposed to a wide range

of chemical, biological, physical and psychological stressors, and because exposure varied with time

of deployment, location, service and occupation, the deployment-nondeployment exposure

classification used in most of these studies is likely to classify veterans inaccurately with respect to

many exposures. As discussed in the report, these limitations are likely to result in underestimates

of the risks of PGW exposure. These studies are also quite limited in their statistical power to detect

increased risks of rare outcomes. Further, many of these studies are limited by their exclusion of a

large proportion of PGW-exposed veterans including those no longer in active service, and National

Guard/Reservists. Most of the birth defect studies, in particular, are limited by their exclusion of

births in civilian hospitals, and diagnoses after the birth hospitalization.

CURRENT STUDIES

ive studies were published by December 1997 which include data on the reproductive health of

PGW veterans. These are: Stretch et al (1995), Penman et al (1996), Iowa Persian Gulf Study

Group (1997), Cowan et al (1997), and Araneta et al (1997). Three of these (Penman, Cowan and

Araneta) examined the relationship between birth defects and PGW exposure. In connection with

the Araneta publication I also discuss an additional source of case ascertainment for Goldenhar

Syndrome, which is the subject of the Araneta study. The remaining two completed studies (Stretch

Page 71

Report of the Special Investigation Unit on Gulf War Illnesses

227

and the Iowa Persian Gulf Study Group) examined PGW exposure and self-reported symptoms,

which included one or more reproductive symptoms or conditions.

Stretchetal(1995) analyze symptoms self-reported by deployed and non-deployed veterans using

questionnaires mailed to 16,167 active duty and reserve personnel in the states of Hawaii and

Pennsylvania.Their low response rate (31%) may be due, in part, to the fact that questionnaires were

distributed to units rather than to individuals. The only reproductive outcome that was reported in

this publication was “menstrual difficulties”. Among active duty respondents, rates of this outcome

were low and similar in deployed and non-deployed (1.7% and 1.5% respectively). Rates among

reservists were higher than those reported by active duty personnel and 34% higher among deployed

than non-deployed (3.1% and 2.3% respectively).

Penman et al (1996) evaluated birth defects and other health problems among children of

veteransof two Mississippi guard units who had served in the PGW. The medical records of all (282)

children of these veterans were reviewed. No concurrent control group was utilized; rates were

comparedto those expected from birth defects surveillance systems and previous surveys. Among 254

(90%) who were interviewed, 54 reported births that were conceived post-deployment. Medical

recordreview was conducted to ascertain birth defects (major and minor), premature births, low birth

weight and other health problems. Five birth defects (three major, two minor), five cases of low birth

weight, and no stillbirths or deaths noted. No increased risks were observed compared to rates from

surveillance systems. No attempt was made to characterize exposure.

The Iowa Persian Gulf Study Group (1997) estimated the prevalence of self-reported symptoms

and illnesses among military personnel deployed during the PGW compared to personnel on active

duty at the same time, but not deployed to the PGW (non-PGW). For this purpose, a stratified

random sample was used to select a study population of 4,886 Iowa veterans. Each individual was

classified as either PGW regular military, PGW National Guard/Reserve, non-PGW regular military

andnon-PGW National Guard/Reserve. Subjects were interviewed regarding a range of medical and

psychiatric conditions. The only reproductive outcome that was reported in this publication was

“symptoms of sexual discomfort”. The prevalence of sexual discomfort among female partners was

approximately doubled among PGW veterans compared to non-PGW veterans (5.0% vs. 2.4% for

regular military and 5.4% vs. 2.1% among National Guard Reservists). Both of these comparisons

were statistically significant at the 95% level.

Cowan et al (1997) studied the relationship between service in the PGW and the overall risk of

birth defects for all US veterans. For this purpose the authors accessed live births at 135 military

hospitals between 1991 and 1993. During that time, 33,998 infants were born to PGW veterans and

41,463 to non-deployed veterans at these hospitals. Birth defects, as routinely recorded on birth

records, were obtained for all live births. Military records were accessed to obtain information on

military service and deployment locations. Exposure was defined simply as “deployment to the

PGW”. While no association between PGW service and birth defects was seen for male service

Page 72

United States Senate Committee on Veterans’ Affairs

228

members, among females there was a small, but statistically significant, increase. Using the broadest

definition of congenital malformations, malformations were noted in 10.32% of births to deployed

veterans versus 9.2% to nondeployed [unadjusted relative risk 1.12, 95% confidence interval (CI)

(1.00 to 1.25)]. After adjustment for race, marital status and branch of service the relative risk was

reduced to 1.07 (95% CI 0.94-1.22). The risk of a severe birth defect was slightly (and not

significantly) lower among children of active duty women than among children of non-deployed

(2.0% versus 2.1%), and both were similar to that reported by the CDC (1.9%). Six commonly

occurring groups of defects were examined and none were associated with PGW exposure either in

menor women. Crude (unadjusted) birth rates were significantly higher in PGW veterans than non-

deployed (95.6 per 1,000 versus 93.3 per thousand). The ratio of male to female births was similar

in deployed and non-deployed veterans.

Thefrequency of occurrence of Goldenhar Syndrome, the most severe group of anomalies to form

an oculo-auricular-vertebral syndrome was estimated in deployed and non-deployed veterans by

Araneta et al (1997). The authors ascertained cases diagnosed at birth among infants born to active-

duty military personnel in military hospital using a broad screen of hospital discharge diagnoses.

Potential cases were identified using 66 ICD-9-CM codes, including the general category “anomaly

of skull and face bones”, and selected ear anomalies. Medical record review by expert reviewers,

blinded to exposure status, was used to identify definite cases of Goldenhar Syndrome among these

potential cases. For all the seven cases identified, the father was the parent in the military. Five of

these were offspring of PGW veterans (14.7 cases per 100,000) and two were offspring of non-

deployed veterans (4.8 cases per 100,000). Thus, the relative risk was elevated (relative risk = 3.0,

95% CI 0.6 – 20.6) though not statistically significantly. The rate observed in PGW exposed was

significantly higher than that reported by either the Hawaii Birth Defects Program or the

Metropolitan Atlanta Congenital Defects program (4-5 per 100,000).

TheAssociation of Birth Defect Children (ABDC) actively solicits the reporting of birth defects.

As part of this activity, 18 cases of Goldenhar Syndrome were identified in veterans; 15 were

deployedto the PGW. Since this registry is more likely to obtain case referrals from exposed veterans,

it cannot be assumed to include a representative sample of unexposed cases.

ONGOING STUDIES

have identified eight ongoing studies that should provide additional information on the risk of

adverse reproductive outcomes among PGW veterans.

Study 3 is a comparative study of pregnancy outcomes among PGW veterans (male and female)

and other active duty personnel. I could not determine whether other outcomes will be examined in

this study.

Page 73

Report of the Special Investigation Unit on Gulf War Illnesses

229

Study4 is examining differences between PGW veterans and non-deployed veterans with respect

to infertility, time to conception and risk of miscarriage. In Phase I of this study a questionnaire was

mailed to a random sample of 16,000 couples (8,000 couples for which one or both deployed to the

PGW, and 8,000 for which neither deployed). Currently the participation rate is 46%. Phase II will

consist of a telephone interview of 5,000 couples to obtain detailed information on exposures and

known risk factors for infertility and miscarriage. The following four categories of married couples

are included: (1) woman served in the PGW; (2) man served in the PGW; (3) woman served in the

military during the PGW, but not in the Gulf area; and (4) man served in the military during the

PGW, but not in the Gulf area.

Study 7 is examining the prevalence of congenital anomalies in the seven states that maintain

active birth defects surveillance systems. These include all birth defects diagnosed in live births

during the first year of life and in still births. This study also proposes to compare rates of preterm

birth,low birth weight and still birth between PGW veterans and non-deployed veterans in the seven

states. Births between 1989 and 1993 will be included in order to compare conceptions prior to,

during, and after the PGW.

The California Birth Defects Monitoring Program (CBDMP) will conduct a feasibility study to

determine; (1) whether Department of Defense (DOD) data on births to active duty military

personnel are sufficient to allow the CBDMP to locate the medical records of these children during

their first year of life; (2) whether hospital record review is possible at DOD facilities, particularly

those which may be closed or have incomplete medical record information; (3) whether DOD

information about structural congenital anomalies is sufficiently accurate, compared to complete

hospital medical record information. This study will also determine if DOD information about the

identity of inactive (separated) personnel can be linked to California vital records and CBDMP files,

neither of which contains social security information.

The most unusual reproductive tract abnormality reported by PGW veterans and their spouses

is the “Gulf War Vaginal Burning Syndrome”. In cases of this syndrome, which can be local or

systemic, severe vaginal burning and pain are reported to occur immediately on contact with the

spouse’s seminal fluid. A study being conducted by the University of Cincinnati has, as its first goal

to determine whether this syndrome in PGW veterans is due to the same immune responses

previously described for cases in the general community. Ten cases in which the husband is an

exposedveteran as well as ten unaffected spouses of exposed veterans will be selected for comparison.

The second goal of the study is to identify seminal plasma proteins involved in the pathogenesis of

this syndrome in spouses of PGW veterans, to determine whether these are the same as the proteins

identified in cases in the general population. For this purpose, five ejaculates, collected over five

consecutive days will be obtained and used to isolate seminal plasma proteins from each male

participant. Women will then be tested for sensitivity to these seminal proteins using skin prick tests.

The third study goal is to determine the effects of PGW exposures on human seminal plasma

obtained from both PGW-exposed and non-exposed males.

Page 74

United States Senate Committee on Veterans’ Affairs

230

The Oregon Health Sciences University study will identify risk factors for Persian Gulf War

Unexplained Illness (PGWUI) in veterans from the northwestern United States. For this purpose a

population-based questionnaire is being mailed to a representative sample of deployed veterans

within the following strata; (1) pre-combat (Desert Shield) only; (2) combat (Desert Storm) only;

(3) post-combat (desert cleanup) only; and (4) two or more of these. By using a sampling strategy

based on period of deployment, the role of potential risk factors such as Pyridostigmine bromide,

special vaccinations and combat stress can be isolated and analyzed. Respondents to the mailed

surveywill provide the study population for the clinical case-control phase of the study. In this phase,

thenature and pattern of exposures in cases of PGWUI and controls will be compared. A total of 250

cases and controls will be recruited for clinical testing within four months of responding to the

survey.

The Department of Veterans Affairs, is conducting a three-phase study which includes a range

of reproductive endpoints. In Phase I, a mailed questionnaire was sent to a random sample of 15,000

PGWveterans and a control sample of 15,000 Gulf-era veterans. To validate responses and evaluate

effects of a low response rate (50%), in Phase II, 2,000 respondents among the deployed, and 2,000

among the non-deployed are being contacted by phone to obtain permission to review medical

records. Further, a random sample of 8,000 non-respondents was selected to compare respondents

and non-respondents. In Phase III physical examinations will be conducted on 1,000 veterans

randomly selected from each group (deployed and non-deployed) as well as their family members.

TheKlemm Analysis Group is conducting a two-year study comparing the health status of 10,000

women who served in the PGW with 10,000 Gulf-era military women. For this purpose a

questionnaire has been developed inquiring about symptoms and conditions including adverse

reproductive outcomes such as infertility, pre-term births, still births and birth defects. Detailed

information on exposures before, during and after the PGW is being elicited.

RECOMMENDATIONS FOR FURTHER STUDY

ost of the studies of the reproductive health of PGW veterans conducted to date include only

limited exposure assessment. The most notable exception is the Oregon Health Sciences

University Study (OHSU), which can be taken as a model for this purpose. The Klemm Analysis

Groupquestionnaire also includes a strong exposure assessment component. The birth defect studies

are particularly weak in this respect, with the exception of the Iowa study, which contains a fairly

extensive exposure component. Therefore, I recommend that a nested-case-control study be

imbedded in Study 7, and a detailed exposure assessment be conducted, perhaps using the OHSU

instrument for consistency and later comparison across studies.

The study of Arenata et al documents an increased risk of Goldenhar Syndrome among

potentially exposed veterans. However, this increase is not statistically significant, possibly due to

small numbers. Therefore, I recommend expanding this study, both to obtain additional cases and

Page 75

Report of the Special Investigation Unit on Gulf War Illnesses

231

toimprove the exposure assessment. To this end I recommend first evaluating the possible additional

cases of Goldenhar Syndrome which have been identified by the ABDC registry. It should be

determined whether any of the 15 exposed cases identified by the ABDC includes cases that should

have been identified by the Arenenta et al study protocol but were inadvertently missed. In other

words, were all ten of the additional exposed cases identified by the ABDC ineligible for the Araneta

study?Conversely, were all five exposed cases identified in Aranenta et al included among the ABDC

cases? It is also recommended that systematic case ascertainment for Goldenhar Syndrome be

expanded in both deployed and nondeployed veterans, including births to separated personnel and

all births to veterans in civilian hospitals. Ascertainment throughout the first year of life, using the

full medical records would be ideal. In addition, it is important to obtain detailed exposure

information on all cases and a sample of controls, perhaps using the Oregon Health Sciences’

questionnaire to obtain exposure information. It is also important to determine whether the cases

of Goldenhar were the first live births born to veterans post-deployment. A causal relationship

between this syndrome and births after one or more healthy babies seems unlikely.

The Oregon Health Sciences’ University is has provided a tentative definition of Persian Gulf

War Unexplained Illness (PGWUI), and is ascertaining cases of PGWUI in the Northwest. Since

it is still uncertain what exposures are most relevant for reproductive illness in PGW veterans, I

recommend looking for an increased incidence of reproductive abnormalities in cases of PGWUI.

It is plausible that these veterans, most affected systemically by these exposures, would also exhibit

more reproductive dysfunction in connection with PGW exposures. This reproductive assessment

should be as complete as possible and should include serum hormone analyses on cases of PGWUI

in the Northwest cohort. In addition, it would be valuable to examine semen quality in male cases.

To date none of these studies has examined semen quality of veterans. Females could be asked to

maintain a detailed dairy recording menstruation, frequency of intercourse and use of contraception

that would allow for a precise analysis of time to conception. If daily urine samples were obtained as

well, assays would provide information on early fetal loss. (See Tier II analyses, Table 6 in the full

report in Appendix L).

Several sources of misclassification in the birth defect studies conducted or underway are listed

above. I recommend that the magnitude of the resulting misclassification be estimated using a

sample of births from Study 7. This analysis would probably have to be limited to the five states that

have active birth defect surveillance for infants up to one year of age throughout the state (thus

excluding California and Georgia). This could be done by obtaining as complete an ascertainment

of birth defects as possible on the selected sample, and then determining how many of these birth

defectswould have been missed if; (1) only the birth record had been used; (2) only military hospitals

had been used; (3) only active-duty personnel had been included. The degree of under reporting

could then be examined as a function of severity of the defect and other covariates.

Page 76

United States Senate Committee on Veterans’ Affairs

232

REFERENCES

Agencyfor Toxic Substance and Disease Registry, Standardizedassessment of birth defects and

reproductive disorders in environmental health field studies. (Ed. G. Terracciano, GK

Lemasters, RW Amler), 1996,NTIS (Publication number PB96-199609), Springfield VA.

Araneta MRG, Moore CA, Olney RS, Edmonds L, Karcher J, McDonough C, Hiliopoulos K,

Schlangen K, Gray GC. Goldenhar Syndrome among infants born in military hospitals to

Persian Gulf War veterans. 7; 1997:56:244-251.

Calle EE, Khoury MJ. Completeness of the discharge diagnoses as a measure of birth defects

recorded in the hospital birth record. AJE 1991; 134:69-77.

Cowan DN, DeFraites RF, Gray GC, Goldenbaum MB, Wishik SM. The risk of birth defects

among children of Persian Gulf War veterans. New Engl J Med. 1997;336:1650-6.

Hill AB. The environment and disease: Association or causation? Proc R Soc Med

1965:58;295-300.

Penman AD, Tarver RS. No evidence of increase in birth defects and health problems among

children born to Persian Gulf War Veterans in Mississippi. Military Medicine 1996; 161:1-6.

Rothman K.J. Modern Epidemiology. 1986, Little Brown and Co. Boston/Toronto.

The Iowa Persian Gulf Study Group. Self –reported illness and health status among Gulf War

veterans. JAMA 1997; 277:238-245.

Waller K, Swan SH, DeLorens G. Spontaneous abortion in relation to exposure to

trihalomethanes in drinking water. Epidemiology (In press. To appear March 1998).

Page 77

Report of the Special Investigation Unit on Gulf War Illnesses

233

GULF WAR REPRODUCTIVE HAZARDS

Prepared by: Melissa McDiarmid, M.D., M.P.H., Associate Professor of Medicine,

Occupational Health Project, University of Maryland;and Director, Depleted Uranium Follow-

Up Program, Baltimore Veterans Affairs’ Medical Center

SUMMARY

eployed Desert Storm/Desert Shield personnel encountered a complex ambient environment

which included chemical, physical and biologic hazards, as well as those of warfare itself. The

complexity of this environmental matrix, the lack of record keeping for various potential exposures

and the passage of time since the conflict have conspired to muddle associations between

environmental exposures and any health effect—including those affecting reproduction.

Further complicating our ability to draw inferences between Gulf War service and reproductive

health harm is the apparent relatively high frequency of spontaneously occurring or “background”

adverse reproductive effects such as infertility, spontaneous abortions (miscarriages) and birth

defects. For example, the conception rate per menstrual cycle of normal couples of reproductive age

havingunprotected intercourse approaches 50%. However, the viable pregnancy rate, i.e., pregnancy

resulting in the birth of a viable child, is about 25% (Soules, 1985). Major fetal malformations occur

in about 3% of liveborn babies, and other impairments such as low birth weight occur in many more

(Kalter and Warkany, 1983).

MECHANISM OF REPRODUCTIVE TOXICITY

lthough there are gender-mediated differences in chemically induced adverse reproductive

outcomes, the majority of well-tested chemicals have demonstrated adverse reproductive

outcomes in both males and females (Paul and Himmelstein, 1988). Adverse effects caused by

reproductive toxicant exposure may be manifested at many sites in the complex pathway of

reproductive function beginning with gametogeneses, and continuing through gamete interaction

(fertilization), embryonic and fetal development and growth, parturition and sexual maturation of

the offspring. Various biologically plausible mechanisms exist that could explain an adverse

reproductive event resulting from a Gulf War exposure. These include both genetically mediated

(mutation) and non-genetically-mediated events.

Page 78

United States Senate Committee on Veterans’ Affairs

234

MALE-MEDIATED EFFECTS

he biologic plausibility of male-mediated reproductive effects has been increasingly considered

and scientific evidence for such effects has grown rapidly. Wyrobek has recently reviewed the

evidence for male-mediated effects manifested beyond fertilization and the multi-generational

context in which reproductive health must be studied (Wyrobek, 1993).

The process of spermatogenesis, characterized by rapid cell development in the testes, is a likely

targetof mutagens which ordinarily interact with dividing cells. Multiple outcomes could result from

such interactions including male infertility and spontaneous abortion. Besides genotoxic

mechanisms, other epigenetic and non-genetic mechanisms modulate male reproductive health at

thelevel of the normal physiologic function and the control of erection and ejaculation. Neurotoxic

agents such as lead (Lancranjan, 1975) and inorganic mercury (Wharton, 1983) may thus affect

sexual function.

A male contribution to spontaneous abortion can be hypothesized via a mutagenic insult to the

sperm (Wyrobek, 1993), paraoccupational exposure resulting in home contamination and maternal

exposure(McDiarmid and Weaver, 1993), concentration of the agent in semen (Stachel et al., 1989)

and direct transmission of the agent on sperm (Yazigi et al., 1991).

REPRODUCTIVE OUTCOMES - BIOLOGIC PLAUSIBILITY

review of the published literature, as well as reports of the Presidential Advisory Committee

(PAC)and the Institute of Medicine (IOM), and minutes of the PAC hearings on Reproductive

Health of Gulf War Veterans and PAC staff consultations on reproductive health was performed.

These sources reflect similar over-arching opinion on the biologic plausibility of reproductive health

harm, methods to ascertain potential health effects, strengths and weaknesses of existing evidence,

and recommendations for the future.

While the prevalence of malformations is variously reported at about 3-5% of newborns,

increasing to 10% after the first two years of life, the general public’s lack of knowledge of this

baselineprevalence has helped to feed fears regarding clusters of birth defects. Epidemiologic studies

todate have failed to show any excess of birth defects among deployed PGW veterans, although some

studies are methodologically limited and others are ongoing. Various experts testified that chasing

clusters is not a good use of the public health dollar when both statistical power and exposure

assessment data are so lacking. As well, very few of the major birth defects have a recognized,

discrete mechanism of causation making associations between outcomes and deployment exposure

difficult.

Page 79

Report of the Special Investigation Unit on Gulf War Illnesses

235

The majority of the testimony was focused on male-mediated effects due to the disproportionate

number of men deployed (about 700,000) versus women (35-50,000). The most consistent

consensus among experts testifying regarding mechanisms of insult resulting in reproductive health

harm focused on germ cell or other damage by a direct-acting mutagenic agent. The most commonly

expectedoutcome from such an exposure would be a spontaneous abortion due to non-viability from

chromosomal aberrations or other insult in the product of conception. Other opportunities for

exposure to a toxic substance included a discussion of transport of a toxicant in seminal fluid and

secondary paraoccupational exposure of the woman to contaminants tracked home by the man on

theclothes and shoes. These mechanisms have been suggested in other occupational/environmental

settings and enjoy more relative consensus than further issues to be discussed.

From p. 160 of his testimony, Dr. Robert Brent states “There is no epidemiological information

to support the suggestion that there is an increase in congenital malformations in the offspring of

Desert Storm... The nature of the malformations, the types of exposures, prior studies involving

human exposures to mutagenic agents and the concept of biologic plausibility make it very unlikely

that there is an increase in the incidence of malformations in offspring.” From p. 161, “We would

not be in the present dilemma if we had a national program of congenital malformation surveillance

involving every birth in the U.S.”

SELF-REPORTED REPRODUCTIVE HEALTH PROBLEMS

here has been concern among PGW veterans regarding reproductive health and the questions

of any adverse reproductive outcomes being deployment - related. Early versions of the CCEP

andVA Gulf War Registry Examination questionnaires have been criticized for inadequate attention

to these outcomes. The VA has since revised its questionnaire to include a more detailed

reproductive health assessment. Dr. Susan Mather, Chief of DVA’s directorate of Environmental

Medicine and Public Health relates that 53,000 veterans were seen using the old questionnaire and

all of these people were mailed the updated questionnaire in the last year. She estimated that about

20,000 had been returned, but were still being analyzed. She also mentioned that phase III of the

Gulf War Registry Health Examination program, although looking at a small subset of the total

population, will include an evaluation of spouses and children. These approaches are appropriate

given the time elapsed since exposure and the attendant epidemiologic problems which arise from

this.

EXPOSURE ASSESSMENT

VERVIEW

The principal resource cited in the variety of reports reviewed regarding the exposure assessment

performed for the presence of reproductive toxicants in the Gulf War theater is the U.S. General

Page 80

United States Senate Committee on Veterans’ Affairs

236

Accounting Office (GAO) report to the chairman, Committee on Veterans Affairs U.S. Senate.

This August, 1994 document addressed a number of questions regarding reproductive health

concernsin the Gulf, only one of which was a charge to characterize potential reproductive toxicants

present. The report identified twenty-one agents distributed among three broad hazard types -

pesticides, oil fires and soil samples, and decontaminating agents. The methodology used by GAO

toassemble this list was only cursorily described to include interviews and document review. As well,

the lack of any non-chemical hazards identified demonstrates a limited understanding of the array

of reproductive toxicants with a potential role in health risk assessment.

The classical approach in performing an exposure assessment begins with assembling candidate

toxicants present in the exposure cohort’s environment. This process was partially completed by the

GAO. Clearly, however, the non-chemical reproductive toxicants must also be cataloged. I will

attempt to at least begin that process later in this report.

After identification of hazards, the next step in an exposure assessment is the determination of

exposure dose. It is this critical step that is always challenging, but in this present scenario, all but

impossible to achieve. As the GAO report states, “... we did not ascertain ... exposure rates for

servicemen and service women for these toxicants... nor perform a risk assessment of these exposures

andhow they might relate to possible reproductive dysfunction...”. In introducing the GAO findings

in testimony before the Senate Committee, Capitol Issue Area Director, Kwai-Cheng Chan stated

that (referring to the twenty-one toxicants cited above), “... the concentration levels of these

compounds are unknown and so are the exposure rates for specific units”.

Therefore, not only are quantitative assignments of exposure dose impossible to make for a given

toxicantand a given service person, or even service unit, a qualitative assignment of exposure cannot

even be reliably made.

Reinforcing this observation is Dr. Grace LeMaster’s testimony to the Presidential Advisory

Committee staff consultation on reproductive health of Gulf War veterans, page 34: “... exposures

cannot be characterized very well. It is my understanding that even vaccination records were not

kept... across all these pregnancies, you have no idea what the exposures are, it’s almost like three

strikes against uncovering anything in this particular situation.”

While the absence of environmental sampling data for the twenty-one toxicants is

understandable given the deployment scenario, as may be understood for who used how much

pyridostigmine, the lack of performance type records, such as vaccination data, is less

comprehensible.

Alsodisconcerting are the anecdotal reports cited in the GAO report. This from page two of that

report (referring to the hazardous exposures in the Gulf) “such as the extensive use of diesel fuel as

Page 81

Report of the Special Investigation Unit on Gulf War Illnesses

237

a sand suppressant in and around encampments, the burning of human waste with fuel oil, the

presence of fuel in shower water, and the drying of sleeping bags with leaded vehicle exhaust...”.

It appears that the most that is possible regarding exposure assessment will be very coarse

assumptions made about certain deployed groups. Refinement as to individual toxicant exposure to

an individual service person will be extremely difficult.

One potential approach to examining at least a “first cut” assessment might be that described in

Dr. Linda Shortridge’s testimony to the Presidential Advisory Committee (page 413). She is

describingexposure assessment methodology that is being used at the University of Oregon and some

of their epidemiologic studies. Regarding exposure assessment, she states, “We do, however, have

an opportunity to compare and contrast groups of veterans who had separate sets of potential

exposure, because they were deployed in the theater of operations for distinct identifiable periods.”

This might be a potentially useful and “transportable” approach to at least qualitatively refine

different populations who, because of calendar time in the theater, were necessarily exposed (or not)

to some different toxic substances.

PIDEMIOLOGY OF

ELF

-R

EPORTED

NVIRONMENTAL

XPOSURES

The 1996 summary of the Department of Defense’s (DOD) Comprehensive Clinical Evaluation

Program(CCEP) for Persian Gulf War Veterans included data for more than 18,000 returned service

members who requested a complete health evaluation. Part of the health evaluation involved

questionnaire completion of a self-reported environmental history. The questions elicited

information about food and water intake, and personal habits, such as smoking and exposure to

passive smoke, as well as questions regarding the more uncommon chemical environmental

exposures. Obviously, the circumstances of exposure, and what determines the individual service

member’s positive response, are variable. Frequency of exposure is also not obtained by this method.

Nonetheless, it gives a sketch of what individual soldiers reported.

A similar battery of questions were included in the Department of Veterans Affairs (DVA)

Persian Gulf Registry questionnaire. Responses elicited are displayed in Table 1. Of interest is the

closeagreement between the two sources on frequency of environmental exposures. Passive cigarette

smoke, diesel exposure, oil fire smoke and tent heater fumes were most commonly reported.

The detail of the questions in both the DOD’s CCEP assessment, and the DVA’s assessment

however, are problematic. Without adding to the number of questions either health assessment

battery currently includes, more refinement of the language used in crafting questions, and some

guidance given to participants about what type of exposure constitutes a clinically important “yes”

to the question, could greatly enhance the value of this information.

Page 82

United States Senate Committee on Veterans’ Affairs

238

Table 1. Frequency of Self-Reported Environmental Exposures in Gulf War Veterans (GWV)

and Active Duty Service Member (ADS)

EXPOSURE

POSITIVE RESPONSE

GWV

(%) ADS

(%)

Passive Cigarette Smoke

88.5

Diesel/Other Fuels/Petrochemical Fumes

90.4

Oil Fire Smoke

72.6

Tank Heater Fumes

66.6

Pyridostigmine Bromide

64.2

Personal Pesticide Use

66.7

Burning Trash/Feces

73.9

N/A

Skin Exposure to Fuel

73.7

N/A

ATE Non-US Food

71.3

Chemical Agent Resistant Paint CARC)

34.5

Solvent /Paints

53.6

Anthrax Immunization

48.7

Ate Contaminated Food

33.2

Microwaves

34.2

N/A

Bathed in Contaminated Water

28.6

Bathed in Non-Military Water

30.5

N/A

Bathed in/Drank Non-US Water

N/A

Botulism Vaccine

26.8

Depleted Uranium

14.2

Nerve Gas

14.1

Took Oral Meds to Prevent Malaria

N/A

Mustard Gas/Blistering Agent

N/A

Chemical Alarm

N/A

Witnessed Casualty

N/A

Witnessed SCUD Attack

N/A

Witnessed Actual Combat

N/A

Wounded in Combat

N/A

a = From Office of Public Health & Environmental Hazards, DVA, “Review of DVA Revised Gulf War Registry & In-Patient Treatment Files

(12/97); N = 10,075

b = Percent based on participants who answered Yes or No (excludes unknown) from DOD CCEP for PGW Veterans (4/96); N = 18,075

Page 83

Report of the Special Investigation Unit on Gulf War Illnesses

239

XPOSURE

SSESSMENT IN

EPRODUCTIVE

EALTH

TUDIES

Most of the studies of reproductive health of Persian Gulf War veterans, whether they be those that

have been completed, or those that are ongoing, suffer from extremely weak exposure assessment.

A majority of the studies use exposure assessment definitions as simple as those deployed being

exposed, and those non-deployed being unexposed for controls. This is clearly inadequate.

Of the studies that are ongoing, again the very large hospital based medical record studies, such

as the Cowan and Calderon studies, as well as the Araneta studies 3, 4 and 7, referred to in Dr.

Swan’s report, all have this significant weakness of having no address of exposure assessment, except

deployment status. Of other studies that are ongoing, several do, however, address environmental

exposures. These include the National Health Survey performed by the Department of Veterans

Affairs; the University of Oregon’s evaluation; and the planned study by the KLEMM group of

10,000 Persian Gulf War deployed women compared to non-deployed woman.

Also of interest, we should mention that the clinical study at the University of Cincinnati,

lookingat seminal plasma hypersensitivity reactions plans to address in a research format some of the

environmental agents which may be active here by introducing some of these environmental

substances in an in vitro system during the assessment of seminal plasma hypersensitivity. This type

of inclusion of environmental effectors in a research protocol is something that we should like to see

in future research studies.

The principal barrier to elucidating what happened or might have happened in the Gulf is the

absence of exposure data. While a list of reproductive toxicants present somewhere in the Gulf

theater can be drawn, its completeness and more importantly, the lack of individual or even military

unit exposure information (by type of agent, concentration, duration of exposure) collude to limit

what information might be drawn from the list of suspect agents. As well, the other confounding

issues, not the least of which is the physiologic and psychologic impact of deployment and war

making,make assigning an association of a specific exposure to a specific adverse outcome extremely

difficult. None the less, there is some limited value in listing the reproductive toxicants present in

the GW theater.

CANDIDATE REPRODUCTIVE TOXICANTS

he Government Accounting Office (GAO) was asked by the Senate Veterans’ Affairs Committee

to specify reproductive toxicants to which deployed troops were potentially exposed. In their

August 1994 report to the Senate Committee, the GAO identified three broad categories of

reproductive toxicants present in the Persian Gulf area: Pesticides, oil fire contaminants and

decontaminating agents. The GAO was unable to supply exposure dose data nor could they

determine which specific units were exposed (if at all) to each of the agents. In addition to the

agentsthe GAO listed, other reviews have also considered exposure to pyridostigmine bromide (PB),

Page 84

United States Senate Committee on Veterans’ Affairs

240

the prophylactic for nerve agent exposure, the various vaccine exposures, possible biologic agent

exposure and mustard agent exposure. Reproductive and developmental toxicity data, as well as

epidemiologic results, where available, are summarized in this section.

Frequently reported birth defects observed in the offspring of pesticide-exposed populations

include neural tube defects, limb reduction defects and facial clefts. (White FM et. al., 1988; Field

andKerr 1979; Balarajan and McDowall, 1983; M. Paul, 1993). Facial clefts and neural tube defects

have also been found in some, but not consistently, in studies of herbicide exposed agricultural

workers and in one study of Vietnam Veterans exposed to the herbicide Agent Orange. Clarity on

this issue has been hampered by lack of exposure data and small sample sizes. Limb reduction defects

have been associated with residence in farming areas and agricultural work (Schwartz DA, et. al.,

1986; Schwartz and Longerfo, 1988).

Maternal pesticide exposure has been found to increase the risk of facial clefts (Brogan et. al.,

1980; Gordon and Shy, 1981) and for all congenital abnormalities. There has also been some

disagreement in the literature regarding increased risk for spina bifida with some reporting an

increase and others not seeing one (White et. al., 1988; Golding and Sladden, 1983). Also of

interest, in an interview study of crop duster pilots and their sibling controls, there was no difference

between groups in number of birth defects in offspring (Roan et. al, 1984).

Generally these studies have examined people with an occupational exposure to pesticides, thus

presuming a relatively longer duration of exposure opportunity and higher exposure intensity than

wouldbe the case for environmentally exposed persons (pesticide users). While adverse reproductive

outcome cannot be ruled out in low level exposures to pesticides (OPs) for example, such adverse

effects are much less likely in the environmentally (low dose) exposed service member population

than in populations occupationally exposed, such as pesticide applicators and farm workers.

OIL FIRES AND SOIL SAMPLES

number of toxic constituents characterize oil fire exposures, with much attention given to the

polycyclic aromatic hydrocarbon benzo (a) pyrene.

ENZO

(

)

PYRENE

Environmental characterization of Kuwait oil-well fires indicated the likely presence of numerous

genotoxic contaminants. Mutagenic products of combustion including polycyclic aromatic

hydrocarbons (PAH) such as benzo (a) pyrene (BAP) were a concern in performing a health risk

assessment for troops deployed to Kuwait in June - September, 1991. As part of a larger health

assessment of these troops, the U.S. Army Environment Hygiene Agency (USAEHA) assessed the

potentialfor mutagenic exposure. The study employed a generic measure of mutagen exposure, sister

chromatid exchange (SCE).

Page 85

Report of the Special Investigation Unit on Gulf War Illnesses

241

Frequenciesof sister chromatid exchange (SCE), a measure of genotoxic exposure, were assessed

in military troops deployed to Kuwait in 1991. Soldiers completed health questionnaires and had

blood collected prior to, during and following deployment to Kuwait. Frequency of spontaneous SCE

was determined on blood samples as a measure of mutagenic exposure. Compared to pre-deployment

baseline SCE frequency means, levels obtained two months into the Kuwaiti deployment were

significantly increased (P < 0.001) and persisted for at least one month after return to Germany.

Outcome was unaffected by known personal SCE effect modifiers including smoking, age, and diet.

This study reveals a highly significant increase in mean SCE for a population of soldiers serving

in Kuwait while oil-well fires burned. This increase persisted for at least one month following return

to their pre-deployment assignment in Germany. Environmental exposures not due to burning oil

fires may have also caused the observed increases in SCE.

The authors concluded that although a statistical increase in SCE frequency has been

demonstratedin troops deployed to Kuwait, implying a genotoxic exposure, multiple candidates exist

as the potential cause of this observation. At present, SCE elevations are thought to measure

exposure to some genotoxic agent, but the long-term health consequences of this phenomenon have

not been determined in this or other populations’ exposure to genotoxicants. (McDiarmid, et al.,

1995).

Another aspect of the Army’s larger health risk assessment determined environmental PAH

exposure which revealed low ambient levels of PAHs in the areas where soldiers were working in

Kuwait. As well, measures of PAH interactions with human blood lymphocyte DNA (PAH-DNA

adducts) and aromatic-DNA adducts were at their lowest levels in Kuwait compared to levels in

Germany. (Poirier M. et al., in preparation).

DECONTAMINATING AGENTS

thylene -glycol-monomethyl ether (2-ME) and a related compound, ethylene glycolmonoethyl

ether (2-EE) are widely used in industry in paints, varnishes, and thinners, and as solvents in the

textile and semi-conductor industries. Health effects data in animals and humans, together with

estimates of large numbers of workers potentially exposed (850,000 U.S. workers, according to

NIOSH) has prompted the OSHA to begin rule-making to limit worker exposure to 0.1 ppm for 2-

ME and 0.5 PPM for 2-EE for an eight hour time weighted average (TWA) exposure. This is the first

OSHA rule-making specifically driven by the adverse reproductive health effects of a workplace

agent.

PYR