Prevalence of chronic fatigue and chemical sensitivities in Gulf Registry Veterans

The Disease Loophole: Index Terms and Their Role in Disease Misclassification

The definitions of disease proffered by philosophers and medical actors typically require that a state of ill health be linked to some known bodily dysfunction before it is classified as a disease. I argue that such definitions of disease are not fully implementable in current medical discourse and practice. Adhering to the definitions would require that medical actors keep close track of the current state of knowledge on the causes and mechanisms of particular illnesses. Yet, unaddressed problems in medical terminology can make this difficult to do. I show that unrecognized misuse of "heterogeneous," "biomarker," and other important health terms-which I call index terms-can misrepresent the current empirical evidence on illness pathophysiology, such that unvalidated illness constructs become mistaken for diseases. Thus, implementing common definitions of disease would require closing this "loophole" in medical discourse. I offer a simple rule that, if followed, could help do just that.

At the Root of 3 “Long” Diseases: Persistent Antigens Inflicting Chronic Damage on the Brain and Other Organs in Gulf War Illness, Long-COVID-19, and Chronic Fatigue Syndrome

Several foreign antigens such as those derived from viruses and bacteria have been linked to long-term deleterious effects on the brain and other organs; yet, health outcomes subsequent to foreign antigen exposure vary depending in large part on the host’s immune system, in general, and on human leukocyte antigen (HLA) composition, in particular. Here we first provide a brief description of 3 conditions characterized by persistent long-term symptoms, namely long-COVID-19, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and Gulf War Illness (GWI), followed by a brief overview of the role of HLA in the immune response to foreign antigens. We then discuss our Persistent Antigen (PA) hypothesis and highlight associations between antigen persistence due to HLA-antigen incongruence and chronic health conditions in general and the 3 “long” diseases above in particular. This review is not intended to cover the breadth and depth of symptomatology of those diseases but is specifically focused on the hypothesis that the presence of persistent antigens underlies their pathogenesis.

Multiple Chemical Sensitivity

Multiple Chemical Sensitivity (MCS), a condition also known as Chemical Sensitivity (CS), Chemical Intolerance (CI), Idiopathic Environmental Illness (IEI) and Toxicant Induced Loss of Tolerance (TILT), is an acquired multifactorial syndrome characterized by a recurrent set of debilitating symptoms. The symptoms of this controversial disorder are reported to be induced by environmental chemicals at doses far below those usually harmful to most persons. They involve a large spectrum of organ systems and typically disappear when the environmental chemicals are removed. However, no clear link has emerged among self-reported MCS symptoms and widely accepted objective measures of physiological dysfunction, and no clear dose-response relationship between exposure and symptom reactions has been observed. In addition, the underlying etiology and pathogenic processes of the disorder remain unknown and disputed, although biologic and psychologic hypotheses abound. It is currently debated whether MCS should be considered a clinical entity at all. Nevertheless, in the last few decades MCS has received considerable scientific and governmental attention in light of the many persons reporting this illness. In this review, we provide a general overview of the history, definition, demographics, prevalence, and etiologic challenges in defining and understanding MCS.

Gene-Toxicant Interactions in Gulf War Illness: Differential Effects of the PON1 Genotype

About 25-35% of United States veterans who fought in the 1990-1991 Gulf War report several moderate or severe chronic systemic symptoms, defined as Gulf War illness (GWI). Thirty years later, there is little consensus on the causes or biological underpinnings of GWI. The Gulf War Era Cohort and Biorepository (GWECB) was designed to investigate genetic and environmental associations with GWI and consists of 1343 veterans. We investigate candidate gene-toxicant interactions that may be associated with GWI based on prior associations found in human and animal model studies, focusing on SNPs in or near ACHE, BCHE, and PON1 genes to replicate results from prior studies. SOD1 was also considered as a candidate gene. CDC Severe GWI, the primary outcome, was observed in 26% of the 810 deployed veterans included in this study. The interaction between the candidate SNP rs662 and pyridostigmine bromide (PB) pills was found to be associated with CDC Severe GWI. Interactions between PB pill exposure and rs3917545, rs3917550, and rs2299255, all in high linkage disequilibrium in PON1, were also associated with respiratory symptoms. These SNPs could point toward biological pathways through which GWI may develop, which could lead to biomarkers to detect GWI or to better treatment options for veterans with GWI.

Experiential avoidance is associated with medical and mental health diagnoses in a national sample of deployed Gulf War veterans

A substantial minority of deployed Gulf War veterans developed posttraumatic stress disorder (PTSD), depression, and several chronic illnesses. Although military combat and exposure to certain nuclear, biological, and chemical agents (NBCs) increase risk for post-deployment health problems, they do not fully explain many Gulf War veteran health diagnoses and are not viable treatment targets. Experiential avoidance (EA; one's unwillingness to remain in contact with unpleasant internal experiences) is a modifiable psychosocial risk factor associated with PTSD and depression in veterans as well as pain and gastrointestinal diseases in the general population. In this study, we recruited a national sample of deployed Gulf War veterans (N = 454) to test the hypothesis that greater EA would be significantly associated with higher lifetime odds of PTSD, depression, "Gulf War Illness" (GWI/CMI), and other chronic illnesses common in this veteran cohort. Participants completed a self-report battery assessing demographic, military-related, and health-related information. Multivariate analyses showed that after adjusting for age, sex, race, combat exposure, and NBC exposure, worse EA was associated with higher lifetime odds of PTSD, depression GWI/CMI, gastrointestinal problems, irritable bowel syndrome, arthritis, fibromyalgia, and chronic fatigue syndrome (ORs ranged 1.25 to 2.89; effect sizes ranged small to large), but not asthma or chronic obstructive pulmonary disease. Our findings suggest medical and mental health providers alike should assess for EA and potentially target EA as part of a comprehensive, biopsychosocial approach to improving Gulf War veterans' health and wellbeing. Study limitations and future research directions are also discussed.

Restoring tripartite glutamatergic synapses: A potential therapy for mood and cognitive deficits in Gulf War illness

Gulf War illness is associated with a combination of exposure to war-related chemical agents and traumatic stress. Currently, there are no effective treatments, and the pathophysiology remains elusive. Neurological problems are among the most commonly reported symptoms. In this study, we investigated the glutamatergic system in the hippocampi of mice exposed to war-related chemical agents and stress. Mice developed Gulf War illness-like symptoms, including mood deficits, cognitive impairments, and fatigue. They exhibited the following pathological changes in hippocampi: elevated extracellular glutamate levels, impaired glutamatergic synapses, astrocyte atrophy, loss of interneurons, and decreased neurogenesis. LDN/OSU-215111 is a small-molecule that can strengthen the structure and function of both the astrocytic processes and the glutamatergic synapses that together form the tripartite synapses. We found that LDN/OSU-215111 effectively prevented the development of mood and cognitive deficits in mice when treatment was implemented immediately following the exposure. Moreover, when symptoms were already present, LDN/OSU-215111 still significantly ameliorated these deficits; impressively, benefits were sustained one month after treatment cessation, indicating disease modification. LDN/OSU-215111 effectively normalized hippocampal pathological changes. Overall, this study provides strong evidence that restoration of tripartite glutamatergic synapses by LDN/OSU-215111 is a potential therapy for Gulf War illness.

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Exposure to Gulf War-related agents and stress causes long-term hippocampal glutamatergic synapses impairment.

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LDN/OSU-215111, a small-molecule that enhances tripartite synapses, normalizes hippocampal deficits in a mouse model of GWI.

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LDN/OSU-215111 effectively ameliorates mood deficits, cognitive impairments, and fatigue in a mouse model of GWI.

Myalgic encephalomyelitis/chronic fatigue syndrome and gulf war illness patients exhibit increased humoral responses to the herpesviruses-encoded dUTPase: Implications in disease pathophysiology

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Gulf War Illness (GWI) are debilitating diseases with overlapping symptomology and there are currently no validated tests for definitive diagnosis of either syndrome. While there is evidence supporting the premise that some herpesviruses may act as possible triggers of ME/CFS, the involvement of herpesviruses in the pathophysiology of GWI has not been studied in spite of a higher prevalence of ME/CFS in these patients. We have previously demonstrated that the deoxyuridine triphosphate nucleotidohydrolases (dUTPase) encoded by Epstein-Barr virus (EBV), human herpesvirus-6 (HHV-6), and varicella-zoster virus (VZV) possess novel functions in innate and adaptive immunity. The results of this study demonstrate that a significant percentage of patients with ME/CFS (30.91-52.7%) and GWI (29.34%) are simultaneously producing antibodies against multiple human herpesviruses-encoded dUTPases and/or the human dUTPase when compared to controls (17.21%). GWI patients exhibited significantly higher levels of antibodies to the HHV-6 and human dUTPases than controls (P = 0.0053 and P = 0.0036, respectively), while the ME/CFS cohort had higher anti-EBV-dUTPase antibodies than in both GWI patients (P = 0.0008) and controls (P < 0.0001) as well as significantly higher anti-human dUTPase antibodies than in controls (P = 0.0241). These results suggest that screening of patients' sera for the presence of various combinations of anti-dUTPase antibodies could be used as potential biomarkers to help identify/distinguish patients with these syndromes and better direct treatment.

CNS findings in chronic fatigue syndrome and a neuropathological case report

Chronic fatigue syndrome (CFS) is characterized as a persistent, debilitating complex disorder of unknown etiology, whereby patients suffer from extreme fatigue, which often presents with symptoms that include chronic pain, depression, weakness, mood disturbances, and neuropsychological impairment. In this mini review and case report, we address central nervous system (CNS) involvement of CFS and present neuropathological autopsy findings from a patient who died with a prior diagnosis of CFS. Among the most remarkable pathological features of the case are focal areas of white matter loss, neurite beading, and neuritic pathology of axons in the white matter with axonal spheroids. Atypical neurons displaying aberrant sprouting processes in response to injury are observed throughout cortical gray and white matter. Abundant amyloid deposits identical to AD plaques with accompanying intracellular granular structures are observed as well. Neurofibrillary tangles are also present in the white matter of the frontal cortex, thalamus and basal ganglia. Taken together, these neuropathological findings warrant further studies into CNS disease associated with CFS.

A pilot registry of unexplained fatiguing illnesses and chronic fatigue syndrome

Background

Chronic fatigue syndrome (CFS) has no diagnostic clinical signs or biomarkers, so diagnosis requires ruling out conditions with similar signs and symptoms. We conducted a pilot registry of unexplained fatiguing illnesses and CFS to determine the feasibility of establishing and operating a registry and implementing an education outreach initiative. The pilot registry was conducted in Bibb County, Georgia. Patient referrals were obtained from healthcare providers who were identified by using various education outreach initiatives. These referrals were later supplemented with self-referrals by members of a local CFS support group. All patients meeting referral criteria were invited to participate in a screening interview to determine eligibility. If patients met registry criteria, they were invited to a one-day clinic for physical and laboratory evaluations. We classified patients based on the 1994 case definition.

Results

We registered 827 healthcare providers. Forty-two providers referred 88 patients, and 58 patients (66%) completed clinical evaluation. Of the 188 CFS support group members, 53 were self-referred and 46 (87%) completed the clinical evaluation. Of the 104 participants completing evaluation, 36% (n = 37) met the criteria for CFS, 17% (n = 18) had insufficient fatigue or symptoms (ISF), and 47% (n = 49) were found to have exclusionary medical or psychiatric illnesses. Classification varied significantly by type of referral but not by previous history of CFS diagnosis. Healthcare providers referred more patients who were classified as CFS as compared to support group referrals in which more exclusionary conditions were identified. Family practice and internal medicine specialties made the most referrals and had the highest number of CFS cases. We conducted three CME events, held three “Meet and Greet” sessions, visited four large clinical health practices and health departments, mailed five registry newsletters, and conducted in-person office visits as part of education outreach, which contributed to patient referrals.

Conclusions

Referrals from healthcare providers and self-referrals from the patient support group were important to registry enrollment. The number of potentially treatable conditions that were identified highlights the need for continued medical management in this population, as well as the limitations of registries formed without clinical examination. Education initiatives were successful in part because of partnerships with local organizations.

An assessment of survey measures used across key epidemiologic studies of United States Gulf War I Era veterans

Over the past two decades, 12 large epidemiologic studies and 2 registries have focused on U.S. veterans of the 1990-1991 Gulf War Era. We conducted a review of these studies' research tools to identify existing gaps and overlaps of efforts to date, and to advance development of the next generation of Gulf War Era survey tools. Overall, we found that many of the studies used similar instruments. Questions regarding exposures were more similar across studies than other domains, while neurocognitive and psychological tools were the most variable. Many studies focused on self-reported survey results, with a range of validation practices. However, physical exams, biomedical assessments, and specimen storage were not common. This review suggests that while research may be able to pool data from past surveys, future surveys need to consider how their design can yield data comparable with previous surveys. Additionally, data that incorporate recent technologies in specimen and genetic analyses would greatly enhance such survey data. When combined with existing data on deployment-related exposures and post-deployment health conditions, longitudinal follow-up of existing studies within this collaborative framework could represent an important step toward improving the health of veterans.

A Disease Register for ME/CFS: Report of a Pilot Study

Background

The ME/CFS Disease Register is one of six subprojects within the National ME/CFS Observatory, a research programme funded by the Big Lottery Fund and sponsored by Action for ME. A pilot study in East Anglia, East Yorkshire, and London aimed to address the problem of identifying representative groups of subjects for research, in order to be able to draw conclusions applicable to the whole ME/CFS population.

While not aiming for comprehensive population coverage, this pilot register sought to recruit participants with ME/CFS in an unbiased way from a large population base. Those recruited are constituting a cohort for long-term follow-up to shed light on prognosis, and a sampling frame for other studies.

Findings

Patients with unidentified chronic fatigue were identified in GP databases using a READ-code based algorithm, and conformity to certain case definitions for ME/CFS determined. 29 practices, covering a population aged 18 to 64 of 143,153, participated.

510 patients with unexplained chronic fatigue were identified. 265 of these conformed to one or more case definitions. 216 were invited to join the register; 160 agreed. 96.9% of participants conformed to the CDC 1994 (Fukuda) definition; the Canadian definition defined more precisely a subset of these. The addition of an epidemiological case definition increased case ascertainment by approximately 4%. A small-scale study in a specialist referral service in East Anglia was also undertaken.

There was little difference in pattern of conformity to case definitions, age or sex among disease register participants compared with subjects in a parallel epidemiological study who declined to participate.

One-year follow-up of 50 subjects showed little change in pain or fatigue scores. There were some changes in conformity to case definitions.

Conclusions

Objective evaluation indicated that the aim of recruiting participants with ME/CFS to a Disease Register had been fulfilled, and confirmed the feasibility of our approach to case identification, data processing, transmission, storage, and analysis. Future developments should include expansion of the ME/CFS Register and its linkage to a tissue sample bank and post mortem tissue archive, to facilitate support for further research studies.

Repeated stress in combination with pyridostigmine Part I: long-term behavioural consequences

Since their return from the first Persian Gulf War, some veterans have complained of a variety of symptoms that were designated as "Gulf War Illness" (GWI). Among other factors, pyridostigmine, used as a prophylaxis treatment against intoxication by nerve agents, has been proposed by many authors as a cause of late social and/or cognitive dysfunction related to GWI. One of the hypotheses placed to explain these behavioural disorders is that operational stress has modified the side effects of pyridostigmine given to soldiers. In an attempt to establish an experimental model of GWI to evaluate the long-term behavioural effects of pyridostigmine administered in stressful conditions, we have developed a new model of repeated stress based on the pole-climbing avoidance technique. We used it to evaluate the effects of pyridostigmine treatment combined to repeated stress over the months following the end of the treatment. We observed that this stress induces impulsiveness and aggressiveness in adult male rat. Moreover, pyridostigmine treatment administered daily 30 min before each stressful session amplifies these behavioural disorders and induces long-term learning dysfunction and slight but significant decrease in phosphocholine level in hippocampus. This suggests that repeated administration of pyridostigmine combined to pole-climbing avoidance (PCA) stress conditions can induce adverse effects in rat central nervous system.

Gulf War Illness: lessons from medically unexplained symptoms

Service in the Persian Gulf in 1991 is associated with increased reporting of symptoms and distress in a proportion of those who served there. Yet despite clear evidence of an increase in symptom burden and a decrease in well being, exhaustive clinical and laboratory based scientific research has failed to document many reproducible biomedical abnormalities in this group. Likewise, there has been no evidence of an increase in disease related mortality. Formal psychiatric disorders are twice as common in Gulf War veterans, as might be expected in the aftermath of any conflict, but this too is insufficient to explain the ill-health observed. Many service personnel who returned unwell believe that they have Gulf War Syndrome, and that their ill-health is due to exposures that they encountered in theatre. Research on multiple exposures to date has not generated a plausible aetiological mechanism for veterans' ill-health. Even if medical research has failed to provide a satisfactory explanation, it remains the case that many of those affected continue to be unwell and disabled some 15 years after returning from combat. For this reason, it is time that more attention is given to developing effective interventions to relieve their ill-health and distress. In this review we discuss the importance of the wider social context, individual illness beliefs and attributions and go on to outline a model of continuing ill-health in Gulf veterans. The review concludes with some suggestions for future research priorities, in particular the need for further qualitative studies to further our understanding of the illness, in order that better treatments may be developed.

Persistence of symptoms in veterans of the First Gulf War: 5-year follow-up

BACKGROUND

During the 1990-1991 Gulf War, approximately 700,000 U.S. troops were deployed to the Persian Gulf theater of operations. Of that number, approximately 100,000 have presented medical complaints through various registry and examination programs.

OBJECTIVES

Widespread symptomatic illness without defining physical features has been reported among veterans of the 1991 Gulf War. We ascertained changes in symptom status between an initial 1995 symptom evaluation and a follow-up in 2000.

METHODS

We assessed mailed symptom survey questionnaires for 390 previously surveyed members of the U.S. Department of Veterans Affairs Gulf War Registry for changes over the 5-year interval in terms of number and severity of symptoms.

RESULTS

For the cohort as a whole, we found no significant changes in symptom number or severity. Those initially more symptomatic in 1995 showed some improvement over time, but remained much more highly symptomatic than those who had lesser initial symptomatology.

CONCLUSIONS

The symptom outbreak following the 1991 Gulf War has not abated over time in registry veterans, suggesting substantial need for better understanding and care for these veterans.

Healthcare utilization and mortality among veterans of the Gulf War

The authors conducted an extensive search for published works concerning healthcare utilization and mortality among Gulf War veterans of the Coalition forces who served during the 1990-1991 Gulf War. Reports concerning the health experience of US, UK, Canadian, Saudi and Australian veterans were reviewed. This report summarizes 15 years of observations and research in four categories: Gulf War veteran healthcare registry studies, hospitalization studies, outpatient studies and mortality studies. A total of 149728 (19.8%) of 756373 US, UK, Canadian and Australian Gulf War veterans received health registry evaluations revealing a vast number of symptoms and clinical conditions but no suggestion that a new unique illness was associated with service during the Gulf War. Additionally, no Gulf War exposure was uniquely implicated as a cause for post-war morbidity. Numerous large, controlled studies of US Gulf War veterans' hospitalizations, often involving more than a million veterans, have been conducted. They revealed an increased post-war risk for mental health diagnoses, multi-symptom conditions and musculoskeletal disorders. Again, these data failed to demonstrate that Gulf War veterans suffered from a unique Gulf War-related illness. The sparsely available ambulatory care reports documented that respiratory and gastrointestinal complaints were quite common during deployment. Using perhaps the most reliable data, controlled mortality studies have revealed that Gulf War veterans were at increased risk of injuries, especially those due to vehicular accidents. In general, healthcare utilization data are now exhausted. These findings have now been incorporated into preventive measures in support of current military forces. With a few diagnostic exceptions such as amyotrophic lateral sclerosis, mental disorders and cancer, it now seems time to cease examining Gulf War veteran morbidity and to direct future research efforts to preventing illness among current and future military personnel.

Chronic multisymptom illness complex in Gulf War I veterans 10 years later

Prior research has demonstrated that shortly after the 1991 Gulf War (Gulf War I), chronic multisymptom illness (CMI) was more common among deployed veterans than among nondeployed veterans. The aims of the current study were to determine the prevalence of CMI among deployed and nondeployed veterans 10 years after Gulf War I, compare the distribution of comorbid conditions, and identify prewar factors associated with CMI. Cross-sectional data collected from 1,061 deployed veterans and 1,128 nondeployed veterans examined between 1999 and 2001 were analyzed. CMI prevalence was 28.9% among deployed veterans and 15.8% among nondeployed veterans (odds ratio = 2.16, 95% confidence interval: 1.61, 2.90). Deployed and nondeployed veterans with CMI had similarly poorer quality-of-life measures and higher prevalences of symptom-based medical conditions, metabolic syndrome, and psychiatric disorders. Diagnoses of prewar anxiety disorders (not related to post-traumatic stress disorder) and depression were associated with CMI among both deployed and nondeployed veterans. Nicotine dependence and veteran-reported physician-diagnosed infectious mononucleosis were associated with CMI among deployed veterans, and migraine headaches and gastritis were associated with CMI among nondeployed veterans. CMI continues to be substantially more prevalent among deployed veterans than among nondeployed veterans 10 years after Gulf War I, but it manifests similarly in both groups. It is likely to be a common, persistent problem among veterans returning from the current Gulf War.

Self-reported chemical sensitivity in Germany: a population-based survey

OBJECTIVES

Environmental clinics are frequented by patients with fears and complaints related to environmental triggers. A dose-independent overreaction to small doses of widely used and generally non-toxic chemicals is referred to as multiple chemical sensitivity (MCS), but no clearly defined clinical syndrome with objective physical findings has been delineated so far. We aimed to obtain information about symptoms, supposed environmental triggers, the frequency of self-reported chemical sensitivity, and of the diagnosis MCS in Germany.

METHODS

We conducted a representative survey among 2032 adult Germans.

RESULTS

We found self-reported chemical sensitivity in 9% and physician-diagnosed MCS in 0.5% of our representative sample. Physical complaints were common in the whole study population and in chemically sensitive individuals, but there was no clear-cut symptom constellation among the latter. The most common complaints were headache, fatigue, sleep disturbances, joint pain, mood changes and nervousness. A subjective connection between complaints and environmental triggers was denied by 67% of the whole group and by 35% of the self-reported chemically sensitive. Factor analysis of environmental triggers suggested that a specific exposure situation rather than chemical similarity is the basis for individual trigger combinations.

CONCLUSIONS

The prevalence of subjective sensitivity towards chemicals is similar to such rates reported from other countries. There is a relatively low awareness of the MCS-concept, and it appears to be diagnosed less frequently than, e.g., in the USA. Since symptoms and triggers in chemically sensitive individuals did not differ from the general population, our data do not suggest the existence of a widespread new syndrome related to chemical sensitivities in Germany. We outline the limitations of self-reported chemical sensitivity as the major criterion for such a contentious diagnosis as MCS.

Can epidemiology clear the fog of war? Lessons from the 1990-91 Gulf War

Despite over US $200 million having been spent researching illnesses following the 1990-91 Persian Gulf War, the nature and cause of such illnesses remains controversial. In this narrative review, we discuss some of the methodological issues that have affected epidemiological studies on this topic. These include low-response rates, ascertainment bias, recall bias, problems identifying suitable control groups, and problems defining the outcomes to study. From this we argue that difficulties have arisen partly owing to the significant delay between the point at which illnesses were first identified by veterans and the reporting of epidemiological studies and that health surveillance should be routine following future deployments.

Gulf War Syndrome: A Toxic Exposure? A Systematic Review

Using the strength-of-conclusion scheme enumerated in Box 2, based on two class II studies, there is probably a causal link between deployment to the Persian Gulf theater of operation and the development of the poorly defined multisymptom illness known as GWS (level B). Based on class IV studies, there is insufficient evidence to determine if exposure to toxins encountered during the Persian Gulf war caused GWS (level U). A major limitation of the literature regarding the GWS is the reliance on self-reporting to measure exposure to putative causal toxins. Although objective measures of toxin exposure in GWV generally is unavailable, modeling techniques to estimate exposure levels to low-level nerve agents and smoke from oil well fires have been developed. It would be useful to determine if exposure levels determined by these techniques are associated with GWS. The lack of a clear case definition GWS also hampers research. Some go even further, claiming that the absence of such a definition renders the condition illegitimate. Although an objective marker to GWS would be useful for studies, the absence of such a marker does not make the syndrome any less legitimate. in essence, GWS merely is a convenient descriptive term that describes a phenomenon: GWV reporting suffering from medically unexplained health-related symptoms. In this sense, it shares much with the other medically unexplained syndromes encountered in practice. The real debate surrounding medically unexplained conditions is not whether or not they exist, but defining their cause. In this regard, investigators fall into two camps. One camp insists that the conditions are caused by a yet-to-be-discovered medical problem, rejecting out of hand the possibility of a psychologic origin. The other camp insists the conditions are fundamentally psychogenic rejecting the possibility of an undiscovered medical condition. The evidence shows, however, that the conditions exists, the suffering is real, and the causes are unknown.

Saudi Arabia-United States collaboration in health research: a formula for success

The aim of this article is to share our experiences from an international collaborative effort to study health outcomes among Saudi Arabian National Guard (SANG) soldiers following the 1991 Gulf War. By paying particular attention to distinct social and religious customs, geopolitical differences, and unique aspects of the health care system, we achieved a successful international collaboration in health research.

Stress, hormones and disease

My postdoctoral training under Dr. Gerard Smith began me on a lifetime of investigation on the role of stress, hormones, and disease. The first set of experiments asked what hormone, if any, best reflected the range of aroused behaviors. We found that catecholamines performed substantially better than glucocorticoids did, despite the belief that glucocorticoids were sensitive indices of stress. But we also learned that hormones themselves were nowhere near as good in monitoring stress than motor behaviors were. In a second set of experiments, we tried to understand how stress affected medical disease. We learned that stress can produce disease in a healthy organism but has its most profound effects when disease already exists. Finally, in the early 1990s, I shifted my focus on stress and disease to a broader problem in behavioral medicine, namely, medically unexplained fatigue and pain. Among the studies we have done investigating these disorders, we looked specifically at veterans of the first Gulf War--many of whom developed problems with severe fatigue. A critical question in the literature asked if unexplained fatigue was simply a physical component of concurrent posttraumatic stress disorder (PTSD). In a large epidemiological study, we found that PTSD tracked stressor intensity in a stepwise fashion, while fatiguing illness increased with stressor intensity only on the milder side of the intensity spectrum. This result indicated that the two ailments are both stress sensitive but dissimilar.

Clinical and laboratory assessment of distal peripheral nerves in Gulf War veterans and spouses

BACKGROUND

The prevalence of symptoms suggesting distal symmetric polyneuropathy (DSP) was reported to be higher among deployed veterans (DV) to the Persian Gulf in 1990-1991 than to control non-deployed veterans (NDV). The authors therefore compared the prevalence of DSP by direct examination of DV and their spouses to control NDV and spouses.

METHODS

The authors performed standardized neurologic examinations on 1,061 DV and 1,128 NDV selected from a cohort of veterans who previously participated in a national mail and telephone survey. Presence of DSP was evaluated by history, physical examination, and standardized electrophysiologic assessment of motor and sensory nerves. Similar examinations were performed without electrophysiologic tests in 484 DV spouses and 533 NDV spouses. Statistical analyses were performed with appropriate adjustments for the stratified sampling scheme.

RESULTS

No differences between adjusted population prevalence of DSP in DV and NDV were found by electrophysiology (3.7% vs 6.3%, p = 0.07), by neurologic examination (3.1% vs 2.6%, p = 0.60), or by the methods combined (6.3% vs 7.3%, p = 0.47). Excluding veterans with non-military service related diseases that may cause DSP did not alter outcomes. DV potentially exposed to neurotoxins from the Khamisiyah ammunition depot explosion did not significantly differ in DSP prevalence compared to non-exposed DV. The prevalence of DSP in DV spouses did not differ from NDV spouses (2.7% vs 3.2%, p = 0.64).

CONCLUSIONS

Neither veterans deployed during the Gulf War era nor their spouses had a higher prevalence of DSP compared to NDV and spouses.

Self-reported ill health in male UK Gulf War veterans: a retrospective cohort study

BACKGROUND

Forces deployed to the first Gulf War report more ill health than veterans who did not serve there. Many studies of post-Gulf morbidity are based on relatively small sample sizes and selection bias is often a concern. In a setting where selection bias relating to the ill health of veterans may be reduced, we: i) examined self-reported adult ill health in a large sample of male UK Gulf War veterans and a demographically similar non-deployed comparison group; and ii) explored self-reported ill health among veterans who believed that they had Gulf War syndrome.

METHODS

This study uses data from a retrospective cohort study of reproduction and child health in which a validated postal questionnaire was sent to all UK Gulf War veterans (GWV) and a comparison cohort of Armed Service personnel who were not deployed to the Gulf (NGWV). The cohort for analysis comprises 42,818 males who responded to the questionnaire.

RESULTS

We confirmed that GWV report higher rates of general ill health. GWV were significantly more likely to have reported at least one new medical symptom or disease since 1990 than NGWV (61% versus 37%, OR 2.7, 95% CI 2.5-2.8). They were also more likely to report higher numbers of symptoms. The strongest associations were for mood swings (OR 20.9, 95%CI 16.2-27.0), memory loss/lack of concentration (OR 19.6, 95% CI 15.5-24.8), night sweats (OR 9.9, 95% CI 6.5-15.2), general fatigue (OR 9.6, 95% CI 8.3-11.1) and sexual dysfunction (OR 4.6, 95%CI 3.2-6.6). 6% of GWV believed they had Gulf War syndrome (GWS), and this was associated with the highest symptom reporting.

CONCLUSIONS

Increased levels of reported ill health among GWV were confirmed. This study was the first to use a questionnaire which did not focus specifically on the veterans' symptoms themselves. Nevertheless, the results are consistent with those of other studies of post-Gulf war illness and thus strengthen overall findings in this area of research. Further examination of the mechanisms underlying the reporting of ill health is required.

Responses to controlled diesel vapor exposure among chemically sensitive Gulf War veterans

OBJECTIVE

A significant proportion of Gulf War veterans (GWVs) report chemical sensitivity, fatigue, and unexplained symptoms resulting in ongoing disability. GWVs frequently recall an association between diesel and petrochemical fume exposure and symptoms during service. The purpose of the present study among GWVs was to evaluate the immediate health effects of acute exposure to chemicals (diesel vapors with acetaldehyde) with and without stress.

METHODS

In a single, controlled exposure to 5 parts per million (ppm) diesel vapors, symptoms, odor ratings, neurobehavioral performance, and psychophysiologic responses of 12 ill GWVs (GWV-I) were compared with 19 age- and gender-matched healthy GWVs (GWV-H).

RESULTS

Relative to baseline and to GWV-H, GWV-I reported significantly increased symptoms such as disorientation and dizziness and displayed significantly reduced end-tidal CO(2) just after the onset of exposure. As exposure increased over time, GWV-I relative to GWV-H reported significantly increased symptoms of respiratory discomfort and general malaise. GWV-I were also physiologically hyporeactive in response to behavioral tasks administered during but not before exposure.

CONCLUSIONS

Current symptoms among GWV-I may be exacerbated by ongoing environmental chemical exposures reminiscent of the Gulf War. Both psychologic and physiologic mechanisms contribute to current symptomatic responses of GWV-I.

After more than 10 years of Gulf War veteran medical evaluations, what have we learned?

Since the 1991 Gulf War, more than 10 years and 1 billion dollars of health evaluations and research have been invested in understanding illnesses among Gulf War veterans. We examined the extensive published healthcare utilization data in an effort to summarize what has been learned. Using multiple search techniques, data as of June 2003 from four different national Gulf War health registries and numerous hospitalization and ambulatory care reports were reviewed. Thus far, published reports have not revealed a unique Gulf War syndrome nor identified specific exposures that might explain postwar morbidity. Instead, they have demonstrated that Gulf War veterans have had an increase in multi-symptom condition, injury, and mental health diagnoses. While these diagnoses are similar to those experienced by other comparable military populations, their explanation is not fully understood. New strategies to identify risk factors for, and to reduce, such postdeployment conditions are summarized.

Work-attributed symptom clusters (darkroom disease) among radiographers versus physiotherapists: associations between self-reported exposures and psychosocial stressors

BACKGROUND

"Darkroom disease" (DRD) has been used to describe unexplained multiple symptoms attributed by radiographers to their work environment. This study determines the prevalence of symptom clusters similar to other unexplained syndromes among (medical radiation technologists (MRTs) as compared with physiotherapists (PTs), and identifies associated work-related (WR) factors.

METHODS

A mail survey was undertaken of members of the professional associations of MRTs and PTs in Ontario, Canada. Questions were included to determine the prevalence and frequency of symptom clusters including abnormal tiredness as well as WR headaches, and symptoms suggestive of eye, nasal, and throat irritation. For the purpose of this study, these are considered to be DRD symptom clusters. Individuals with doctor-diagnosed asthma were excluded from our analyses.

RESULTS

Overall, 63.9% of MRTs and 63.1% of PTs participated. Criteria for DRD were met by 7.8% of 1,483 MRTs and 1.8% of 1,545 PTs [odds ratio, OR 4.8 (confidence interval, CI 3.1-7.5); (P < 0.0001)]. Both occupations showed significant associations between responses reflecting psychosocial stressors and DRD. Those with this symptom cluster were more likely to report additional symptoms than those without, and MRTs with DRD symptoms reported significantly more workplace chemical exposures.

CONCLUSIONS

Findings suggest excess symptoms consistent with DRD among MRTs versus PTs, and there were associations among those meeting our definition of DRD with self-reported irritant exposures and psychosocial stressors.

Hippocampal dysfunction in Gulf War Syndrome. A proton MR spectroscopy study

The pathogenesis of Gulf War Syndrome (GWS) is not clearly understood. Data exist to suggest that GWS may originate from a combination of chronic fatigue and sensitivity to the exposure of exogenous agents. Since the head region of hippocampus is highly vascularized and thus vulnerable to toxic substances in circulation, we postulated that hippocampal impairment occurs in GWS. To test this, single volume localized in vivo proton MR spectroscopy (MRS) studies of the left and right hippocampi of consenting Gulf War veterans (N=15; 10 with GWS, and 5 without GWS) and control Vietnam veterans (N=6) were conducted in accordance with approved human study protocols. The N-acetyl aspartate (NAA) to creatine and choline to creatine ratios were computed from the spectra. The NAA/creatine ratio of the GWS group (N=10) was found to be significantly lower than that of the entire control group (N=11) or the unaffected GW control group (N=5). No laterality differences were observed among any of the three groups. The choline/creatine ratio of the GWS group was not different from that for either control group. To check the existence of any relationship between age and the NAA/creatine ratios, the entire study population was grouped into those below or above the median age (44.3 years). It was found that the NAA/Cre ratio of the younger group (only Gulf War veterans) was significantly lower than that of the older group. The lower NAA/creatine ratio for the GWS group points to the existence of hippocampal dysfunction.

Interdisciplinary diagnostics in environmental medicine--findings and follow-up in patients with chronic medically unexplained health complaints

PROBLEM

In patients attributing their chronic, medically unexplained complaints to environmental factors the greatest challenge is to overcome their disabling belief in toxicogenic explanations.

METHOD

Patients presenting with health complaints that they attributed to environmental causes in an environmental outpatient department (EOPD) within a university medical center in Germany were studied. An interdisciplinary review of previously diagnosed medical conditions, current clinical consultations, personal risk communication and therapeutic advice is presented. Additionally, patient contentedness, complaint development, and belief in environmental attribution in a follow-up interview are given.

RESULTS

The open, prospective study comprises 51 patients reporting more than one complaint. Symptoms had lasted for more than 3 years in 63% of the cases. Seventy percent attributed their complaints to more than one environmental cause. The clinical diagnostic procedure reduced the number of prediagnosed clinical conditions by 50%. Numerous foregoing environmental laboratory analyses had overestimated toxicologically relevant findings. These were not confirmed in 80% (8/10) of the cases. In 8% (n = 4) of the patients a relevant environmental or occupational medical condition was found. A mental or behavioral condition was not considered to have first priority in explaining all complaints in 43% (22/51) of the patients. Among these, mostly respiratory or skin-related diseases were found. All patients contacted participated in a follow-up study after a minimum of 21 months. Sixty-seven percent reported having felt that they were taken seriously, 38% felt better after the beginning of the study, and 45% were no longer certain about the importance of the environmental attribution. Since 83% of the patients with a preceding residential diagnosis of MCS or SBS still believed in environmental causes of their complaints in the follow-up study, we conclude that these prediagnoses appear to be a risk for persisting attribution of the environmental factor. About one third (37%) of these patients with complaints that had not been medically explained by an organic condition during interdisciplinary diagnostics had meanwhile consulted a psychotherapist.

CONCLUSIONS

Interdisciplinary diagnostics and scientifically based risk assessment in a specialized clinical center were effective and mostly well accepted by the patients and resulted in reduced attribution of complaints to environmental conditions. No indication was found that patients with complaints not medically explained by organic conditions were managed less successfully by this approach. Considering the high costs that these patients have previously caused, it appears valuable to apply an interdisciplinary diagnostic strategy.

Multiple chemical sensitivity in male painters; a controlled provocation study

The purpose of the present study was to examine whether male painters reporting multiple chemical sensitivity (MCS) differ from their matched controls (male painters without such sensitivity) during controlled chamber challenges to singular and mixtures of odorous chemicals with respect to: (1) Subjective rating of symptoms (i.e., symptoms related to central nervous system (CNS) and symptoms related to irritation) and sensations of smell elicited by low-level chemical exposures. (2) Changes in serum prolactin and cortisol levels, changes in nasal cavity and eye redness as a result of the various exposures. Moreover, background assessments were made regarding mental well-being, sense of coherence (SOC) as well as state of anxiety and depression in both groups. The MCS and control group consisted of 14 and 15 male painters respectively. Regarding background assessments of mental well-being, anxiety, depression and SOC, statistically significant differences were obtained between painters with MCS and their controls. During the controlled chamber challenges, neither difference regarding sensations of smell nor development of CNS related symptoms were seen between MCS and control group. In contrast, subjective rating of symptoms related to irritation (i.e., eyes, nose, throat, skin, and breathing difficulties) was significant higher in subjects with MCS. No differences between the groups as a result of the different exposures were seen concerning nasal cavity, eye redness and serum cortisol levels. However, a trend (P = 0.056) between the groups was measured regarding a decline of serum prolactin levels in the MCS group. This is a relatively small study with a limited number of volunteers; and no definitive conclusions can be drawn concerning the above findings. But it is the first controlled challenge study that incorporates similarly exposed groups (painters) recruited from a community rather than from a clinical population.

Effects of posttraumatic stress disorder on cardiovascular stress responses in Gulf War veterans with fatiguing illness

Abnormal cardiovascular stress responses have been reported in Gulf War veterans with chronic fatigue. However, many of these veterans also suffer from posttraumatic stress disorder (PTSD), which could potentially explain the reported abnormalities. To test this hypothesis, 55 Gulf veterans (GVs) with chronic fatigue syndrome (CFS) or idiopathic chronic fatigue (ICF) were stratified into groups with (N=16) and without (N=39) comorbid PTSD, and were compared to healthy Gulf veterans (N=47) on cardiovascular responses to a series of stressors. The CFS/ICF with PTSD group had lower blood pressure responses to speech and arithmetic tasks, and more precipitous declines and slower recoveries in blood pressure after standing up than the controls. Similar trends in the CF/ICF group without PTSD were not significant, however. Both CFS/ICF groups had blunted increases in peripheral vascular resistance during mental tasks. However, only the veterans with comorbid PTSD had diminished cardiac output responses to the mental stressors and excessive vasodilatory responses to standing. Symptoms of posttraumatic stress were significant predictors of hypotensive postural responses, but only in veterans reporting a significant exposure to wartime stress. We conclude that comorbid PTSD contributes to dysregulation of cardiovascular responses to mental and postural stressors in Gulf veterans with medically unexplained fatiguing illness, and may provide a physiological basis for increased somatic complaints in Gulf veterans with symptoms of posttraumatic stress.

Patient activism and the struggle for diagnosis: Gulf War illnesses and other medically unexplained physical symptoms in the US

We examine Gulf War illnesses--which include the fatigue, joint pain, dermatitis, headaches, memory loss, blurred vision, diarrhea, and other symptoms reported by Gulf War veterans--in relation to other medically unexplained physical symptoms such as multiple chemical sensitivity, chronic fatigue syndrome, and fibromyalgia. Our intent is to examine the diagnosis negotiations involved in these mysterious diseases, by showing the different forms of legitimacy involved in such interactions. Factors involved in diagnostic legitimacy are: diagnostic legitimacy in the medical community, lay acceptance of the diagnosis, uncertainty in looking for causes, and social mobilization. We conclude by noting that research may not be able to find any cause for these diseases/conditions; hence, it may be necessary to embrace medical uncertainty, and also to accept patient experience in order to facilitate diagnosis, treatment, and recovery process. Such a change can alter patients' expectations and taken-for-granted assumptions about medicine, and perhaps in turn reduce the frequency with which dissatisfied individuals form illness groups that mobilize to challenge what they see as an unresponsive medical system.

Chemical sensitivity in symptomatic Cambodia veterans

Following their participation in a United Nations peacekeeping operation in Cambodia (1992-1993), Dutch veterans complained of symptoms similar to those reported by Gulf War veterans. The authors conducted a matched case-control study to evaluate 76 symptomatic and 32 matched asymptomatic Cambodia veterans on the basis of data collected by postal questionnaire. The number of symptomatic veterans who reported having used insect repellants that contained N,N,-diethyl-meta-toluamide (DEET) during the mission in Cambodia was significantly higher, compared with asymptomatic veterans. The percentage of veterans who reported feeling ill following brief exposures to chemicals such as paint or pesticides was equal in both groups, but the percentage was low compared with the results of other studies of Multiple Chemical Sensitivity Syndrome. The current study was limited by self-report and time delay (potential recall bias) between deployment to Cambodia and the time of survey. Nevertheless, the study results did not support the hypothesis that symptoms in the total group of Cambodia veterans could be related to Multiple Chemical Sensitivity Syndrome.

Are syndromes in environmental medicine variants of somatoform disorders?

To date, relatively little is known about the etiology, pathophysiology, diagnosis, therapy, prevention and prognosis of environment-related syndromes like multiple chemical sensitivity (MCS), idiopathic environmental intolerance (IEI), sick building syndrome (SBS), chronic fatigue syndrome (CFS), candida syndrome (CS) and burnout syndrome (BS). Part of the reason is that these syndromes have not been clearly defined and classified in scientific categories distinct from each other, and that they show clinical similarities to classified somatoform disorders. Furthermore, there are at least three possible explanations for the existence of these syndromes: (1) The syndromes may result from the interaction of environmental factors, individual susceptibility and psychological factors (i.e., how they are perceived and seen by the patient); (2) they may reflect socially and culturally accepted methods of expressing distress; and/or (3) they may be iatrogenic. Despite all the uncertainties in evaluation of environmental syndromes, physicians have the duty to take the affected person's problems seriously. A comprehensive systematic classification which better accounts for these complex clinical manifestations is long overdue. Until these syndromes are well defined, the terms used for them should definitely not be applied to connote a specific disease process.

Neurobehavioral effects of pesticides: state of the art

The authors have reviewed the literature on neurobehavioral toxicity of pesticides to assess the status of knowledge on this matter. Some data suggest that exposure to DDT and fumigants may be associated with permanent decline in neurobehavioral functioning and increase in psychiatric symptoms, but, due to the limited number of studies available and the scarce knowledge on exposure levels, no firm conclusion can be drawn. Data on subjects acutely poisoned with organophosphorous compounds suggest that an impairment in neurobehavioral performance and, in some cases, emotional status may be observed as a long-term sequela, but the possibility still remains that these effects were only an aspecific expression of damage and not of direct neurotoxicity. Studies carried out on subjects chronically exposed to organophosphates, but never acutely poisoned, do not provide univocal results but the slight changes consistently observed in sheep dippers suggest the need of focusing on activities characterized by relatively higher exposure levels. In general, the main limits of existing knowledge are the variability of the testing methods used, which makes it difficult to compare the results of single studies, and the scarce knowledge on exposure levels. A promising approach may be the conduction of prospective longitudinal or cohort studies, where exposure and dose assessment can be more easily controlled, or the evaluation of cohorts of workers a priori selected for the availability of environmental and biological monitoring data. The follow up of the populations under study may give an answer at the problem of the prognostic significance of the observed changes. Also the protocols used to assess neurobehavioral functioning need to be standardized.

Perceived exertion in fatiguing illness: Gulf War veterans with chronic fatigue syndrome

PURPOSE

It has been reported that ratings of perceived exertion (RPE) are elevated in chronic fatigue syndrome (CFS). We have challenged this notion by examining perceived exertion in civilian females with CFS and expressing the data relative to exercise capacity (%[OV0312]O(2max)). The purpose of the present investigation was to further examine RPE during exercise in a unique population of CFS patients, Gulf veterans (GV).

METHODS

Thirty-four GV (N = 15 CFS, 42 +/- 8 yr; N = 19 healthy, 43 +/- 5 yr) performed a maximal exercise test on a cycle ergometer. After a 3-min warm-up, exercise intensity increased by 30 W every minute until exhaustion. RPE were obtained during the last 15 s of each minute using Borg's CR-10 scale.

RESULTS

With the exception of peak [OV0312]E, there were no significant differences in any peak exercise variables. Repeated measures ANOVA revealed significantly higher RPE at each power output examined (F(1,32) = 16.4, P < 0.001). Group differences in RPE remained significant when analyzed relative to peak [OV0312]O(2) (F(1,32) = 7.2, P = 0.01). Both group main effects and the interaction were eliminated when self-reported fatigue symptoms were controlled for in the analyses. Power functions for RPE as a function of relative oxygen consumption were not different between groups and were significantly greater than a linear value of 1.0 (1.6 +/- 0.3 for both groups, P < 0.02).

CONCLUSIONS

Our results show that RPE are greater in GV with CFS regardless of whether the data were expressed in terms of absolute or relative exercise intensity. However, self-reported fatigue associated with CFS eliminated the group differences. These results suggest that GV with CFS were unique compared with their civilian counterparts. Future research aimed at determining the influence of preexisting fatigue on RPE during exercise is warranted.

Symptom patterns among Gulf War registry veterans

OBJECTIVES

We identify symptom patterns among veterans who believe they suffer from Gulf War-related illnesses and characterize groups of individuals with similar patterns.

METHODS

A mail survey was completed by 1161 veterans drawn from the Gulf War Health Registry.

RESULTS

An exploratory factor analysis revealed 4 symptom factors. A K-means cluster analysis revealed 2 groups: (1) veterans reporting good health and few moderate/severe symptoms, and (2) veterans reporting fair/poor health and endorsing an average of 37 symptoms, 75% as moderate/severe. Those in Cluster 2 were more likely to report having 1 or more of 24 medical conditions.

CONCLUSIONS

These findings are consistent with previous investigations of symptom patterns in Gulf War veterans. This multisymptom illness may be more fully characterized by the extent, breadth, and severity of symptoms reported.

Multiple chemical sensitivity and idiopathic environmental intolerance (part two)

Multiple chemical sensitivity/idiopathic environmental intolerance (MCS/IEI) is a commonly used diagnostic term for a group of symptoms without apparent organic basis. The symptoms are characteristic of dysfunction in multiple organ systems. They wax and wane fluctuate according to exposure to low levels of chemical agents in the patient's environment, and sometimes begin after a distinct environmental change or injury such an industrial accident or chemical introduced after remodeling. Although traditional medical organizations have not agreed on a definition for this syndrome, it is being increasingly recognized and makes up an increasing percentage of the caseload at occupational/environmental medical clinics.Part two of this review article discusses diagnosis, clinical examination, long-term follow up of MCS/IEI, and the role of physicians, research on odor and treatment, diseases with similar symptoms, and further research regarding MCS/IEI patients.

NMDA sensitization and stimulation by peroxynitrite, nitric oxide, and organic solvents as the mechanism of chemical sensitivity in multiple chemical sensitivity

Multiple chemical sensitivity (MCS) is a condition where previous exposure to hydrophobic organic solvents or pesticides appears to render people hypersensitive to a wide range of chemicals, including organic solvents. The hypersensitivity is often exquisite, with MCS individuals showing sensitivity that appears to be at least two orders of magnitude greater than that of normal individuals. This paper presents a plausible set of interacting mechanisms to explain such heightened sensitivity. It is based on two earlier theories of MCS: the elevated nitric oxide/peroxynitrite theory and the neural sensitization theory. It is also based on evidence implicating excessive NMDA activity in MCS. Four sensitization mechanisms are proposed to act synergistically, each based on known physiological mechanisms: Nitric oxide-mediated stimulation of neurotransmitter (glutamate) release; peroxynitrite-mediated ATP depletion and consequent hypersensitivity of NMDA receptors; peroxynitrite-mediated increased permeability of the blood-brain barrier, producing increased accessibility of organic chemicals to the central nervous system; and nitric oxide inhibition of cytochrome P450 metabolism. Evidence for each of these mechanisms, which may also be involved in Parkinson's disease, is reviewed. These interacting mechanisms provide explanations for diverse aspects of MCS and a framework for hypothesis-driven MCS research.

Chronic fatigue in a population-based study of Gulf War veterans

Fatigue has been associated with illness in veterans of the Gulf War; however, few studies have confirmed self-reported fatigue by using clinical evaluation, and symptomatic veterans have not been evaluated with established criteria for Chronic Fatigue Syndrome (CFS). The authors describe the frequency and clinical characteristics of CFS in a sample of veterans residing in the northwestern United States. The sample was selected randomly from U.S. Department of Defense databases of troops deployed to southwest Asia during the Gulf War. The selected individuals were invited to participate in a clinical case-control study of unexplained illness. Of 799 survey respondents eligible for clinical evaluation, 178 had fatigue symptoms. Of the 130 veterans who were evaluated clinically, 103 had unexplained fatigue, and 44 veterans met the 1994 U.S. Centers for Disease Control criteria for CFS. In this population, the authors estimated a minimum prevalence of any unexplained fatigue to be 5.1%, and of CFS to be 2.2%. The estimated prevalence was greater among females than among males. Cases were similar to healthy controls, as determined by laboratory tests and physical findings. In comparison to several clinical studies of CFS patients, the authors of this study found a lower proportion of veterans who reported a sudden onset of symptoms (19%) vs. a gradual onset (50%). Although it has previously been suggested that veterans of the Gulf War suffer from higher rates of chronic fatigue than the general population, the study results described herein--on the basis of clinical examination of a population-based sample of veterans-actually indicate that an increased rate may indeed exist. Gulf War veterans with unexplained fatigue should be encouraged to seek treatment so that the impact of these symptoms on overall quality of life can be reduced.

An interdisciplinary therapeutic approach for dealing with patients attributing chronic fatigue and functional memory disorders to environmental poisoning--a pilot study

Nonspecific symptoms and a general feeling of ill health that is difficult to objectify are the commonest health problems with which patients present to an Environmental Medicine Outpatient Department (OPD). Of this group, a great proportion meets the classification criteria for Chronic Fatigue Syndrome (CFS) or Functional Memory Disorders in association with Idiopathic Chronic Fatigue (FMD-ICF). This is a longitudinal study of the OPD of Environmental Medicine, Freiburg University Hospital, Germany, to determine the feasibility and impact of an interdisciplinary therapeutic approach (self-help program, acupuncture, psychosomatic support by group interventions) in 8 patients with CFS, FMD-ICF, or CFS in association with self-reported Multiple Chemical Sensitivities (sr-MCS). The intervention took into consideration the patients' need for treatment of physical aspects of their disease. This is an important step to motivate patients into required psychosomatic support. Although none of the patients was willing to accept psychosomatic support or psychotherapy at study outset, acceptance of psychosomatic group interventions was high during the study course. Additionally five patients started with personal counseling at the Psychosomatic Clinic, and, without feeling stigmatized, 4 patients started with specific psychotherapy. The patients' quality of life showed no increase after four months, but, as shown by the Sum-Score of SF-36, it had improved significantly at the end of the study, which covered eight months' treatment (p = 0.015). Two follow-up investigations showed that this improvement probably persisted in part (mainly in the dimensions mental health, social function, physical role function, and vitality). In conclusion our interdisciplinary therapeutic approach indicates successful treatment of patients attributing CFS, CFS/sr-MCS, and FMD-ICF to environmental poisoning. We now plan to conduct a randomized controlled trial in the future.

Common etiology of posttraumatic stress disorder, fibromyalgia, chronic fatigue syndrome and multiple chemical sensitivity via elevated nitric oxide/peroxynitrite

Three types of overlap occur among the disease states chronic fatigue syndrome (CFS), fibromyalgia (FM), multiple chemical sensitivity (MCS) and posttraumatic stress disorder (PTSD). They share common symptoms. Many patients meet the criteria for diagnosis for two or more of these disorders and each disorder appears to be often induced by a relatively short-term stress which is followed by a chronic pathology, suggesting that the stress may act by inducing a self-perpetuating vicious cycle. Such a vicious cycle mechanism has been proposed to explain the etiology of CFS and MCS, based on elevated levels of nitric oxide and its potent oxidant product, peroxynitrite. Six positive feedback loops were proposed to act such that when peroxynitrite levels are elevated, they may remain elevated. The biochemistry involved is not highly tissue-specific, so that variation in symptoms may be explained by a variation in nitric oxide/peroxynitrite tissue distribution. The evidence for the same biochemical mechanism in the etiology of PTSD and FM is discussed here, and while less extensive than in the case of CFS and MCS, it is nevertheless suggestive. Evidence supporting the role of elevated nitric oxide/peroxynitrite in these four disease states is summarized, including induction of nitric oxide by common apparent inducers of these disease states, markers of elevated nitric oxide/peroxynitrite in patients and evidence for an inductive role of elevated nitric oxide in animal models. This theory appears to be the first to provide a mechanistic explanation for the multiple overlaps of these disease states and it also explains the origin of many of their common symptoms and similarity to both Gulf War syndrome and chronic sequelae of carbon monoxide toxicity. This theory suggests multiple studies that should be performed to further test this proposed mechanism. If this mechanism proves central to the etiology of these four conditions, it may also be involved in other conditions of currently obscure etiology and criteria are suggested for identifying such conditions.

The problem of Gulf War syndrome

Following a war with widespread attention to and concern over the potential for numerous biological and chemical warfare exposures, some Gulf War veterans returned home and developed various illnesses. Although some of these illnesses are readily diagnosable, the so-called Gulf War syndrome has remained a controversial and nebulous diagnosis. It is characterized by multiple, subjective symptoms, and by a lack of objective pathology. To date, the search for a single disease entity and a biological model to explain this illness has been unsuccessful. Wars have long affected the health of veterans in multiple ways, and a single disease entity is not likely as a viable explanation for these outcomes. Given the nature of the illness, and its overlap with many other controversial chronic illnesses, we suggest that the biopsychosocial model may provide a better solution to this diagnostic conundrum.

Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome

The prevalence of chronic widespread pain in the general population in Israel was comparable with reports from the USA, UK, and Canada. Comorbidity with fibromyalgia (FM) resulted in somatic hyperalgesia in patients with irritable bowel syndrome. One sixth of the subjects with chronic widespread pain in the general population were also found to have a mental disorder. Mechanisms involved in referred pain, temporal summation, muscle hyperalgesia, and muscle pain at rest were attenuated by the N-methyl-D-aspartate (NMDA) antagonist, ketamine, in FM patients. Delayed corticotropin release, after interleukin-6 administration, in FM was shown to be consistent with a defect in hypothalamic corticotropin-releasing hormone neural function. The basal autonomic state of FM patients was characterized by increased sympathetic and decreased parasympathetic systems tones. The severity of functional impairment as assessed by the Medical Outcome Survey Short Form (SF-36) discriminated between patients with widespread pain alone and FM patients. Chronic fatigue syndrome (CFS) occurred in about 0.42% of a random community-based sample of 28,673 adults in Chicago, Illinois. A significant clinical overlap between CFS and FM was reported. Cytokine dysregulation was not found to be a singular or dominant factor in the pathogenesis of CFS. A favorable outcome of CFS in children was reported; two thirds recovered and resumed normal activities. No major therapeutic trials in FM and CFS were reported over the past year.

Chemical sensitivity and chronic fatigue in Gulf War veterans: a brief report

The foci of this brief report are to (1) describe the prevalence of chemical sensitivity (CS) and chronic fatigue (CF) symptomatology and of presumptive multiple CS and CF syndrome diagnoses, and (2) explore the potential overlap between one purported case definition (i.e., chronic multi-symptom illness) and these unexplained symptom syndromes in a well-characterized group of Gulf War veterans. The number of subjects with CS and CF symptomatology and presumptive multiple CS and CF syndrome diagnoses was higher in the Gulf War-deployed group compared with a group deployed to Germany during the Gulf War. However, the percent differences were not significant when comparing the presumptive diagnoses of multiple CS and CF syndrome. The characteristic differences between the groups and the overlap with chronic multi-symptom illness are also discussed.

Environmental sensitivities: prevalence of major symptoms in a referral center: the Nova Scotia Environmental Sensitivities Research Center Study

Although the phenomenon of environmental sensitivities (ES) has no clear etiology nor well-accepted pathophysiology, affected individuals experience symptoms that cause varying levels of dysfunction. Through a dedicated, government-funded research and treatment center, a detailed questionnaire covering 217 symptoms in 13 systems was mailed in 1997-1998 to 812 individuals referred to the center by physicians. A total of 385 (47%) questionnaires were returned, and data were analyzed on 351 individuals. Participants tended to be women (80%), middle-aged individuals (37% age 40-49 years), and those in higher educational groups (28% completed university), but there was wide variation in demographic variables. General symptoms such as difficulty concentrating, fatigue, forgetfulness, and irritability dominated the overall prevalence of symptoms since the start of their illness. Those related to irritation such as sneezing, itchy or burning eyes, and hoarseness or loss of voice were more common after exposure to environmental irritants. Ranking of symptoms using severity scores was consistent between men and women. Overall scores were higher in women, in participants who were separated or divorced, and in low-income groups. The type and consistency of symptoms experienced after exposure to triggering substances may not fit a purely psychogenic theory.

Gulf War illnesses: causes and controversies

Numerous studies investigating Gulf War illnesses have documented that, while Gulf War veterans are no more likely to die or be hospitalized, they complain of more symptoms than their non-Gulf War counterparts and are more likely to seek medical treatment and disability retirement. Proposed causes include exposure to chemical and microbiological agents and psychological factors. No definitive evidence has emerged to link chemical exposures to these illnesses, although epidemiological studies and animal research suggest possible synergistic effects to multiple exposures. Microbiological agents are unlikely to be etiologic. Psychological and cultural factors undoubtedly contribute to a number of illnesses, but their exact role requires further study. Based on a review of the scientific and popular literature, it is reasonable to conclude that Gulf War illnesses remain a poorly defined group of symptom clusters. Well-controlled research from independent groups is required to answer the numerous questions that have arisen from this illness outbreak.