Health and exposures of United Kingdom Gulf war veterans. Part II: The relation of health to exposure

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.

Women in novel occupational roles: mental health trends in the UK Armed Forces

BACKGROUND

There is uncertainty about whether women in the military have more psychological symptoms than men and whether psychological symptoms have increased over time. The aims of this study were to assess changes in psychological symptoms in military women over time, to compare them with men, and assess the effect of deployment.

METHODS

Two cross-sectional studies based on random samples of the Armed Forces were used to assess the effects of deployment to the Gulf and Iraq Wars. We selected for the analyses all the women and a 20% random sample of men who completed a questionnaire stratified by rank. We assessed psychological distress, number of symptoms, post-traumatic stress reaction (PTSR), chronic fatigue and alcohol misuse.

RESULTS

There has been an increase in psychological symptoms, including alcohol misuse, in those not deployed to the Gulf or Iraq Wars, especially in women. The odds ratios for PTSR [5.82 (95% CI: 1.27-26.71)], multiple symptoms [8.49 (1.97-36.65)] and alcohol misuse [6.20 (2.09-18.37)] were higher in women than in men in the non-deployed samples. Psychological distress and chronic fatigue was more common in women, and alcohol misuse, was more common in men. In women, psychological symptoms were positively associated with deployment in the Gulf War, but not the Iraq War.

CONCLUSION

Psychological symptoms in the Armed Forces have increased over time regardless of gender, in those not deployed. The association between gender and psychological symptoms has not changed over time. The deployment effect in women is similar to that described in men.

The challenges of exposure assessment in health studies of Gulf War veterans

A variety of exposures have been investigated in Gulf War veterans' health studies. These have most commonly been by self-report in a postal questionnaire but modelling and bio-monitoring have also been employed. Exposure assessment is difficult to do well in studies of any workplace environment. It is made more difficult in Gulf War studies where there are a number and variety of possible exposures, no agreed metrics for individual exposures and few contemporary records associating the exposure with an individual. In some studies, the exposure assessment was carried out some years after the war and in the context of media interest. Several studies have examined different ways to test the accuracy of exposure reporting in Gulf War cohorts. There is some evidence from Gulf War studies that self-reported exposures were subject to recall bias but it is difficult to assess the extent. Occupational exposure-assessment methodology can provide insights into the exposure-assessment process and how to do it well. This is discussed in the context of the Gulf War studies. Alternative exposure-assessment methodologies are presented, although these may not be suitable for widespread use in veteran studies. Due to the poor quality of and accessibility of objective military exposure records, self-assessed exposure questionnaires are likely to remain the main instrument for assessing the exposure for a large number of veterans. If this is to be the case, then validation methods with more objective methods need to be included in future study designs.

Gulf War illness: a view from Australia

Australia sent a small, mostly naval, deployment to the 1991 Gulf War. When papers and media concerns arose about unexplained Gulf War illnesses in Gulf War troops from other countries, Australia decided to undertake its own study of Australian veterans. Undertaking a later study, more than 10 years after the Gulf War, allowed us to incorporate some methodological improvements on previous research, such as the inclusion of a face-to-face health assessment where more objective health data could be collected in addition to using a postal questionnaire. Despite the different Gulf War experience for the mostly naval Australian group, there were remarkable consistencies in the patterns of multiple symptom reporting found in overseas studies, including the fact that no unique symptom clusters were identified. In general, this excess symptom reporting was not found to occur with excesses in more objective measures of physical health. These objective physical measures included a wide range of haematological, biochemical and serological markers, a physical examination, spirometry and a step test of fatigability. In contrast, several psychological disorders, including anxiety, post-traumatic stress disorder, depression and substance abuse, were found to occur in excess in the Australian Gulf War group and were associated with Gulf War psychological stressors. These findings have helped raise awareness in Australia of psychological health problems in deployed military personnel.

Immunological dysfunction, vaccination and Gulf War illness

One candidate cause of Gulf War illness is vaccination against infectious diseases including medical counter-measures against biological weapons. One influential theory has suggested that such mass-vaccination caused a shift in immune response to a Type 2 cytokine pattern (Th2), which it was suggested was accompanied by a chronic fatigue syndrome-like illness. This article critically appraises this theory. We start by examining epidemiological evidence, which indicates that single vaccines are unlikely to be a substantial cause of Gulf War illness, but that there was a modest relationship with multiple vaccines, which was strongest in those vaccinated while deployed to the Gulf. These relationships may be affected by recall bias. We conclude by examining the results of immunological studies carried out in veterans or in a relevant setting in vitro. The balance of evidence from immunological studies on veterans returning from the War, including those developing multi-symptom illness, is that the immune response has not become polarized towards Th2. In summary, the epidemiological evidence for a multiple vaccine effect on Gulf War-related illness remains a potentially important aetiological lead, but mechanistic studies available at this stage do not identify any immunological basis for it.

The burden of psychological symptoms in UK Armed Forces

OBJECTIVE

To assess the prevalence of psychological symptoms during periods of relatively low deployment activity and the factors associated with each psychological health outcome.

METHODS

A survey of 4500 randomly selected UK service personnel was carried out in 2002. The questionnaire included the General Health Questionnaire (GHQ-12), the post-traumatic stress disorder checklist (PCL), 15 symptoms and an assessment of alcohol intake.

RESULTS

A total of 20% were above cut-offs for GHQ-12, 15% for symptoms, 12% for alcohol intake and 2% for PCL. Gender, age, excessive drinking and smoking were independently associated with most outcomes of interest. Number of deployments was independently associated with multiple symptoms and excessive drinking. High post-traumatic stress disorder score was more frequent in the Army and in lower ranks.

CONCLUSIONS

Psychological symptoms are highly prevalent in UK Armed Forces. Many risk factors are associated with measures of psychological ill-health.

Long-term mortality amongst Gulf War Veterans: is there a relationship with experiences during deployment and subsequent morbidity?

BACKGROUND

Gulf War Veterans have previously been shown to have, in the short-term, an excess risk of death from 'external' (i.e. non-disease) causes of death. This study aims to determine whether there remains an excess of non-disease-related deaths in Gulf Veterans, 13 years after deployment, and, for the first time, to determine whether there is a relationship between experiences reported in the Gulf, post-war symptoms, and subsequent mortality experience.

METHODS

We conducted a cohort study with follow-up from April 1, 1991 (the end of the Gulf War) to June 30, 2004. Participants were 53 462 Gulf War Veterans and a cohort of military personnel, matched for age-group, sex, rank, service and level of fitness, who were not deployed to the Gulf. The outcome measure used was mortality as recorded on the NHS central register.

RESULTS

There is no difference, 13 years after the end of the Gulf War, in the overall mortality experience of Gulf War Veterans. The excess in non-disease-related deaths previously reported is confined to the initial 7 years of follow-up [mortality rate ratio (MRR) 1.31, 95% confidence interval (CI) 1.06-1.63] rather than the more recent period (MRR 1.05, 95% CI 0.83-1.33). Overall experiences reported during Gulf deployment did not influence subsequent risk of dying, but there was non-significant increased risk of dying from a disease-related death (MRR 1.99, 95% CI 0.98-4.04) associated with reported exposure to depleted uranium and of a non-disease-related death associated with reporting handling of pesticides (MRR 2.05, 95% CI 0.91-4.61). Reporting of morbidity in the health surveys conducted was not related to future risk of death.

CONCLUSION

The higher rates of non-disease-related deaths in Gulf War Veterans is not evident in the period of follow-up since 1997. Neither the excess morbidity reported in health surveys nor the experiences during deployment significantly influenced future mortality. The two non-significant associations found (reported depleted uranium exposure and disease death, reporting handling pesticides and non-disease deaths) need to be considered in the context of the number of possible associations examined and potential biases-although they are biologically plausible.

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.

Assessing the potential health impact of the 1991 Gulf War on Saudi Arabian National Guard soldiers

BACKGROUND

There has been considerable publicity that the 1991 Gulf War may have caused a wide array of health problems in military personnel. Although post-war health outcomes have been studied in US, British, Canadian, Danish, and other deployed troops, this issue has not been previously evaluated in coalition forces native to the Gulf region.

METHODS

A collaborative team of US and Saudi health researchers was assembled, data sources evaluated, and hospitalizations among Saudi Arabian National Guard (SANG) soldiers between 1991 and 1999 analysed. Multivariate modelling was used to evaluate differences between 8342 soldiers exposed to combat at Al Khafji and a comparison group of 7270 soldiers in the Riyadh area.

RESULTS

Among 15 612 SANG soldiers, we identified 148 with at least one hospitalization over the 9 years following the war. The adjusted rate of hospitalization was higher in the combat-exposed group (risk ratio (RR) = 1.80, 95% confidence interval (CI) 1.25-2.59). No unusual patterns of diagnoses were found and, because the overall number of hospitalizations was low, the absolute difference in risk was found to be very small.

CONCLUSIONS

This is the first reported epidemiological investigation of post-war hospitalizations among coalition forces native to the Gulf region that participated in the 1991 Gulf War. A very small increase in hospitalizations was identified in SANG soldiers exposed to combat at Al Khafji. However, because of data limitations, the clinical relevance of this finding should be interpreted with caution. Future collaborative studies to better understand the health effects of deployment should be encouraged.

Symptoms and medical conditions in Australian veterans of the 1991 Gulf War: relation to immunisations and other Gulf War exposures

AIMS

To investigate whether Australian Gulf War veterans have a higher than expected prevalence of recent symptoms and medical conditions that were first diagnosed in the period following the 1991 Gulf War; and if so, whether these effects were associated with exposures and experiences that occurred in the Gulf War.

METHODS

Cross-sectional study of 1456 Australian Gulf War veterans and a comparison group who were in operational units at the time of the Gulf War, but were not deployed to that conflict (n = 1588). A postal questionnaire was administered and the likelihood of the diagnosis of self-reported medical conditions was assessed and rated by a medical practitioner.

RESULTS

Gulf War veterans had a higher prevalence of all self-reported health symptoms than the comparison group, and more of the Gulf War veterans had severe symptoms. Increased symptom reporting was associated with several exposures, including having more than 10 immunisations, pyridostigmine bromide tablets, anti-biological warfare tablets, pesticides, insect repellents, reportedly being in a chemical weapons area, and stressful military service experiences in a strong dose-response relation. Gulf War veterans reported psychological (particularly post-traumatic stress disorder), skin, eye, and sinus conditions first diagnosed in 1991 or later more commonly than the comparison group. Over 90% of medical conditions reported by both study groups were rated by a medical practitioner as having a high likelihood of diagnosis.

CONCLUSION

More than 10 years after the 1991 Gulf War, Australian veterans self-report all symptoms and some medical conditions more commonly than the comparison group. Further analysis of the severity of symptoms and likelihood of the diagnosis of medical conditions suggested that these findings are not due to over-reporting or to participation bias.

Respiratory health status of Australian veterans of the 1991 Gulf War and the effects of exposure to oil fire smoke and dust storms

BACKGROUND

Since the 1991 Gulf War concerns have been raised about the effects on veterans' health of exposures to Kuwaiti oil fire smoke and to dust storms.

METHODS

A cross sectional study compared 1456 Australian Gulf War veterans with a randomly sampled military comparison group (n = 1588). A postal questionnaire asked about respiratory conditions, exposures, medications, tobacco use, demographic characteristics, and military service details. During a medical assessment, spirometric tests and a physical examination were performed and a respiratory questionnaire was administered.

RESULTS

The response rate for the Gulf War veteran group was 80.5% and for the comparison group 56.8%. Australian Gulf War veterans had a higher than expected prevalence of respiratory symptoms and respiratory conditions suggesting asthma (OR 1.4; 95% CI 1.1 to 1.9) and bronchitis first diagnosed since the Gulf War (OR 1.9; 95% CI 1.2 to 3.1) but did not have poorer lung function or more ventilatory abnormalities than the comparison group. Veterans who reported exposure to oil fire smoke had slightly poorer forced vital capacity (difference between means -0.10 l; 95% CI -0.18 to -0.03) and those exposed to dust storms had a slightly better peak expiratory flow rate (difference between means 12.0 l/min; 95% CI 0.6 to 23.4) than veterans who did not report exposure. Veterans who were in the Gulf at or after the start of the oil fires had more respiratory conditions suggesting asthma (OR 1.7; 95% CI 1.0 to 2.9) than those who completed their deployment before this time.

CONCLUSIONS

Increased self-reporting of respiratory symptoms, asthma, and bronchitis by veterans was not reflected in poorer lung function. The findings do not suggest major long term sequelae of exposure to oil fire smoke or dust storms.

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.

Aluminum inclusion macrophagic myofasciitis: a recently identified condition

The authors conclude that the persistence of aluminum hydroxide at the site of intramuscular injection is a novel finding which has an exact significance that remains to be established fully. It seems mandatory to evaluate possible long-term adverse effects induced by this compound, because this issue has not been addressed (in the past, aluminum hydroxide was believed to be cleared quickly from the body). If safety concerns about the long-term effects of aluminum hydroxide are confirmed, novel and alternative vaccine adjuvants to rescue vaccine-based strategies should be proposed to ensure the enormous benefit for public health that these vaccines provide worldwide.

Reported Exposures, Stressors, and Life Events Among Gulf War Registry Veterans

We investigated the association of 15 exposures, 10 stressors, and 18 life events with illness symptoms reported by 978 veterans who believe they suffer from Gulf War-related illnesses. A mail survey was completed by veterans (60% response rate) from the Gulf War Health Registry. Variables most associated with high symptom group membership were reported chemical/biologic warfare (CBW), concerns with infection and faulty equipment, feelings of mistrust in the military, and disability leading to work stoppage within 2 years after the war. These data suggest that belief in CBW exposure, and the experience of war stress and serious negative life events after the war, are important concomitants of Gulf War illness. Models seeking to explain Gulf War symptoms need to incorporate a range of exposure and psychosocial factors to fully account for important influences.

Creatine phosphate kinase elevations signaling muscle damage following exposures to anticholinesterases: 2 sentinel patients

In this study, the authors describe 2 patients who experienced confirmed exposures to anticholinesterases that commenced in the 1970s. Subsequently, elevations in creatine phosphate kinase (CPK) were initially detected more than a decade following the first acute exposure. Beginning in the early 1980s, the patients suffered from progressive generalized muscle weakness, chronic fatigue, myopathy, neuropathy, and severe neurobehavioral impairments. Previous occupational exposures included pyridostigmine, as well as isopropyl methylphosphonofluoridate (percutaneous lethal dose [LD50] < 28 mg/kg body weight), and 1 patient had exposure to agricultural organophosphates. The authors hypothesize that the workers' CPK elevations, first detected more than a decade following acute exposures to anticholinesterases, were sentinel events for impending muscle damage and necrosis. Many Gulf War veterans with Gulf War disease who reported exposures to anticholinesterases 1 decade earlier currently suffer from vague neuromuscular and cognitive impairments. Therefore, medical programs for Gulf War veterans with Gulf War Syndrome should include surveillance for elevated CPK, abnormalities of neuromuscular conduction, and genetic susceptibility, and they should promote therapeutic trials for palliation.

Paraoxonase in Persian Gulf War veterans

Serum paraoxonase (PON1) is responsible for the metabolism of organophosphates in serum, and PON1 activity is a major determinant of their toxicity in humans. There have been reports linking lowered PON1 activity to physical symptoms after deployment to the Persian Gulf War (PGW) of 1990 to 1991. Therefore, the object of this study was to determine (1) whether PON1 activity was decreased among symptomatic PGW veterans compared with asymptomatic PGW veterans and (2) to determine whether PGW veterans as a whole had lower PON1 activity compared with other military control groups. This was a case control study nested in occupational cohort study of military personnel. Four groups of military personnel were identified from a large epidemiological study of health effects of deployment to the PGW and Bosnia: (1) symptomatic PGW veterans, n = 115; (2) healthy PGW veterans, n = 95; (3) symptomatic Bosnia peacekeeping veterans, n = 52; and (4) symptomatic nondeployed military controls, n = 85. The main outcome measures were PON1 activity and genotype for PON1-55 and -192. We found significant differences in PON1 activity among these four groups, and although the two Gulf groups did not differ in PON1 activity, those deployed to the Gulf had significantly lower PON1 activity compared with the non-PGW groups (median difference = 70.9; 95% CI: 20.2, 121.5, P = 0.012). These differences were not explained by a range of potential confounders, or differences in PON1 coding region polymorphisms. PON1 activity is reduced in PGW veterans compared with military control groups. The effect is independent of ill health in PGW veterans.

Comments on the Institute of Medicine's 2002 report on the safety of anthrax vaccine

In April 2002, the prestigious Institute of Medicine of the National Academy of Sciences issued a final report on the safety and effectiveness of the anthrax vaccine currently in use by the United States military. It concluded that the present vaccine was completely safe and effective, but ignored evidence of several recent research studies from three different nations that have implicated vaccines, often including anthrax vaccine, in the epidemiology of Gulf War illnesses. Omissions and limitations of that report are discussed.

The Anthrax Vaccine Program: an analysis of the CDC's recommendations for vaccine use

The anthrax vaccine was never proved to be safe and effective. It is one cause of Gulf War illnesses, and recent vaccinees report symptoms resembling Gulf War illnesses. The vaccine's production has been substandard. Without adequate evaluation, the Food and Drug Administration recently approved (retrospectively) significant changes made to the vaccine's composition since 1990. The vaccine's mandatory use for inhalation anthrax is "off-label." A skewed review of the vaccine literature by the Centers for Disease Control and Prevention (CDC) led to remunerative collaborative research with the army, involving civilian volunteers. Despite acknowledging possible fetal harm, the CDC offered the vaccine to children and pregnant women. New trends could weaken prelicensure efficacy and safety review of medical products intended for biodefense and avoid manufacturer liability for their use.