Risk factors for multisymptom illness in US Army veterans of the Gulf War

A multidimensional network of factors associated with long COVID in the French population

BACKGROUND

Various factors associated with long COVID have been evidenced, but the heterogeneity of definitions and epidemiological investigations has often hidden risk pathways relevant for understanding and preventing this condition.

METHODS

This nationwide random sampling survey conducted in France after the Omicron waves in autumn 2022 assessed eight sets of factors potentially associated with long COVID in a structured epidemiological investigation based on a conceptual model accounting for the relationships between these sets of factors. A representative sample of 1813 adults of whom 55% were infected with SARS-CoV-2 was assessed for infection dates and context, post-COVID symptoms and these factors. Four definitions of long COVID, including the World Health Organisation's, were used.

RESULTS

Female sex, household size (≥2), low financial security, negative impact of COVID-19 pandemic on occupation and work conditions, number of comorbidities (≥2), presence of respiratory disease, mental and sensory disorders, number of SARS-CoV-2 infections (≥2) and initial symptoms (≥6), perceived high severity of COVID-19 are positively and consistently associated with long COVID. Age ≥ 75 years, retirement, SARS-CoV-2 vaccination (≥2 doses) and good perceived information regarding long Covid are negatively associated with the condition.

CONCLUSIONS

The broad spectrum of factors confirmed here strongly suggests that long COVID should be regarded not only as a direct complication of SARS-CoV-2 infection but also as driven by a broader network of contextual, medical, psychological and social factors. These factors should be better considered in strategies aimed at limiting the long COVID burden in the general population.

US military veterans' perceived concordance with their providers regarding persistent physical symptoms prospectively predicts satisfaction with care and adherence to care plans

BACKGROUND

Medically unexplained, persistent physical symptoms and syndromes are commonly seen in primary care. These are debilitating for patients and difficult to treat, causing frustration for patients and providers.

PURPOSE

This study investigates how well US military veterans with multiple persistent physical symptoms (PPS), called Gulf War illness (GWI), agree with their healthcare providers about their illness. This agreement, called perceived concordance, is hypothesized to influence veterans' satisfaction with care, adherence to care plans, and disability levels.

METHODS

Participants were 230 veterans with GWI deployed to the 1990-1991 Gulf War who were recruited from Veteran Affairs primary care and War Related Illness and Injury Study Centers (WRIISCs). Veterans' GWI perceptions and perceived concordance with their providers regarding GWI were assessed at a medical visit. Veterans' self-reported satisfaction with care, adherence to care plans, and disability levels were measured at 1 week, 1 month, and 6 months post-baseline.

RESULTS

Bivariate correlations indicated that veterans' GWI-related illness perceptions were related to veterans' satisfaction with care and reports of functional disability. Beyond these effects, veterans' perceived concordance with the provider regarding GWI was positively associated with satisfaction over time (e.g., fixed-effect estimate = 0.36, P < .001 for 1-week follow-up) and adherence to care plans (fixed-effect estimate averaged across all timepoints = 0.03, P = .03) but was unrelated to reported disability.

CONCLUSIONS

Veterans' perceived concordance with their providers about GWI seems to be important for patient satisfaction and adherence to care plans. More research with longer-term follow-up is needed to understand how perceived concordance might influence disability levels and the outcome of care plans.

Association of deployment characteristics and exposures with persistent ill health among 1990-1991 Gulf War veterans in the VA Million Veteran Program

BACKGROUND

Veterans of the 1990-1991 Gulf War have experienced excess health problems, most prominently the multisymptom condition Gulf War illness (GWI). The Department of Veterans Affairs (VA) Cooperative Studies Program #2006 "Genomics of Gulf War Illness in Veterans" project was established to address important questions concerning pathobiological and genetic aspects of GWI. The current study evaluated patterns of chronic ill health/GWI in the VA Million Veteran Program (MVP) Gulf War veteran cohort in relation to wartime exposures and key features of deployment, 27-30 years after Gulf War service.

METHODS

MVP participants who served in the 1990-1991 Gulf War completed the MVP Gulf War Era Survey in 2018-2020. Survey responses provided detailed information on veterans' health, Gulf War exposures, and deployment time periods and locations. Analyses determined associations of three defined GWI/ill health outcomes with Gulf War deployment characteristics and exposures.

RESULTS

The final cohort included 14,103 veterans; demographic and military characteristics of the sample were similar to the full population of U.S. 1990-1991 Gulf War veterans. Overall, a substantial number of veterans experienced chronic ill health, as indicated by three defined outcomes: 49% reported their health as fair or poor, 31% met Centers for Disease Control and Prevention criteria for severe GWI, and 20% had been diagnosed with GWI by a healthcare provider. Health outcomes varied consistently with veterans' demographic and military characteristics, and with exposures during deployment. All outcomes were most prevalent among youngest veterans (< 50 years), Army and Marine Corps veterans, enlisted personnel (vs. officers), veterans located in Iraq and/or Kuwait for at least 7 days, and veterans who remained in theater from January/February 1991 through the summer of 1991. In multivariable models, GWI/ill health was most strongly associated with three exposures: chemical/biological warfare agents, taking pyridostigmine bromide pills, and use of skin pesticides.

CONCLUSIONS

Results from this large cohort indicate that GWI/chronic ill health continues to affect a large proportion of Gulf War veterans in patterns associated with 1990-1991 Gulf War deployment and exposures. Findings establish a foundation for comprehensive evaluation of genetic factors and deployment exposures in relation to GWI risk and pathobiology.

Current Health Status of Gulf War Deployed and Gulf War Era Veterans Who Use Veterans Affairs Health Care

Background: Although some recent studies have examined the health of female Gulf War (GW) deployed and non-deployed GW era veterans, these all relied on self-report, which can be inaccurate and subject to recall bias. This study investigated the current health of GW deployed and non-deployed GW era female and male veterans using Veterans Health Administration (VHA) electronic health records (EHR). Methods: We performed a cohort study of deployed GW and non-deployed GW era veterans, identified from a list from the Defense Manpower Data Center (DMDC). We used the VA-Frailty Index (VA-FI), calculated with VHA administrative claims and EHR, as a proxy measure of current health. Results: We identified 402,869 veterans (351,496 GW deployed; 51,3373 non-deployed GW era; 38,555 female) in VHA databases. Deployed female veterans had the highest VA-FI (i.e., were frailest) despite being younger than deployed and non-deployed male veterans and non-deployed female veterans. Compared with deployed male veterans, deployed females were more likely to be pre-frail, mildly, and moderately frail. Health differences between deployed and non-deployed female veterans were more prominent among older (60+ years) than younger (<60 years) veterans. Conclusions: Mirroring reports from recent, smaller survey studies of users and non-users of VA health care, findings from this cohort study indicate that deployed female GW veterans who use VA health care are frailer and have more health deficits than non-deployed female GW era and deployed male GW veterans. Because deployed female GW veterans appear to have additional health care needs, this may warrant increased outreach from women's clinics at VA hospitals.

Characterizing 1991 Gulf War women veterans from the Boston Biorepository and Integrative Network for Gulf War Illness: Demographics, exposures, neuroimaging and cognitive outcomes

Objective: Gulf War Illness (GWI) is a debilitating multisymptom condition that affects nearly a third of 1990-91 Gulf War (GW) veterans. Symptoms include pain, fatigue, gastrointestinal issues, and cognitive decrements. Our work has shown that GWI rates and potential causes for symptoms vary between men and women veterans. Studies have documented neuropsychological and neuroimaging findings mostly in men or combined sex datasets. Data are lacking for women veterans due to lack of power and repositories of women veteran samples. Methods: We characterized GW women veterans in terms of demographics, exposures, neuropsychological and neuroimaging outcomes from the newly collated Boston, Biorepository and Integrative Network (BBRAIN) for GWI. Results: BBRAIN women veterans are highly educated with an average age of 54 years. 81% met GWI criteria, 25% met criteria for current PTSD, 78% were white, and 81% served in the Army. Exposure to combined acetylcholinesterase inhibitors (AChEi) including skin pesticides, fogs/sprays and/or pyridostigmine bromide (PB) anti-nerve gas pill exposure resulted in slower processing speed on attentional tasks and a trend for executive impairment compared with non-exposed women. Brain imaging outcomes showed lower gray matter volumes and smaller caudate in exposed women. Conclusions: Although subtle and limited findings were present in this group of women veterans, it suggests that continued follow-up of GW women veterans is warranted. Future research should continue to evaluate differences between men and women in GW veteran samples. The BBRAIN women sub-repository is recruiting and these data are available to the research community for studies of women veterans.

Anthrax Vaccination, Gulf War Illness, and Human Leukocyte Antigen (HLA)

We report on a highly significant, positive association between anthrax vaccination and occurrence of Gulf War Illness (GWI) in 111 Gulf War veterans (42 with GWI and 69 controls). GWI was diagnosed in 47.1% of vaccinated veterans but only in 17.2% of non-vaccinated veterans (Pearson χ2 = 7.08, p = 0.008; odds ratio = 3.947; relative risk = 2.617), with 1.6x higher GWI symptom severity in vaccinated veterans (p = 0.007, F-test in analysis of covariance). Next, we tested the hypothesis that the susceptibility to GWI following anthrax vaccination could be due to inability to make antibodies against the anthrax protective antigen (PA), the key protein contained in the vaccine. Since the first step in initiating antibody production would be the binding of PA peptide fragments (typically 15-amino acid long [15-mer]) to peptide-binding motifs of human leukocyte antigen (HLA) Class II molecules, we assessed the binding-motif affinities of such HLA specific molecules to all linear 15-mer peptide fragments of the anthrax PA. We identified a total of 58 HLA Class II alleles carried by the veterans in our sample and found that, of those, 18 (31%) were present in the vaccinated group that did not develop GWI but were absent from the vaccinated group who developed GWI. Remarkably, in silico analyses revealed very high binding affinities of peptide-binding motifs of those 18 HLA alleles with fragments of anthrax vaccine PA, leading to the successful production of anti-PA antibodies. Conversely, the absence of these protective HLA alleles points to a reduced ability to develop antibodies against PA, thus resulting in harmful PA persistence and development of GWI.

Cognitive decrements in 1991 Gulf War veterans: associations with Gulf War illness and neurotoxicant exposures in the Boston Biorepository, Recruitment, and Integrative Network (BBRAIN) cohorts

BACKGROUND

During deployment, veterans of the 1991 Gulf War (GW) were exposed to multiple war-related toxicants. Roughly a third of these veterans continue to exhibit neurotoxicant induced symptoms of Gulf War Illness (GWI), a multi-faceted condition that includes fatigue, pain and cognitive decrements. When studied empirically, both deployed veterans with exposures and those who meet the criteria for GWI are more likely to show deficits in the area of neuropsychological functioning. Although studies have shown cognitive impairments in small sample sizes, it is necessary to revisit these findings with larger samples and newer cohorts to see if other areas of deficit emerge with more power to detect such differences. A group of researchers and clinicians with expertise in the area of GWI have identified common data elements (CDE) for use in research samples to compare data sets. At the same time, a subgroup of researchers created a new repository to share these cognitive data and biospecimens within the GWI research community.

METHODS

The present study aimed to compare cognitive measures of attention, executive functioning, and verbal memory in a large sample of GWI cases and healthy GW veteran controls using neuropsychological tests recommended in the CDEs. We additionally subdivided samples based on the specific neurotoxicant exposures related to cognitive deficits and compared exposed versus non-exposed veterans regardless of case criteria status. The total sample utilized cognitive testing outcomes from the newly collated Boston, Biorepository, Recruitment, and Integrative Network (BBRAIN) for GWI.

RESULTS

Participants included 411 GW veterans, 312 GWI (cases) and 99 healthy veterans (controls). Veterans with GWI showed significantly poorer attention, executive functioning, learning, and short-and-long term verbal memory than those without GWI. Further, GW veterans with exposures to acetylcholinesterase inhibiting pesticides and nerve gas agents, had worse performance on executive function tasks. Veterans with exposure to oil well fires had worse performance on verbal memory and those with pyridostigmine bromide anti-nerve gas pill exposures had better verbal memory and worse performance on an attention task compared to unexposed veterans.

CONCLUSIONS

This study replicates prior results regarding the utility of the currently recommended CDEs in determining impairments in cognitive functioning in veterans with GWI in a new widely-available repository cohort and provides further evidence of cognitive decrements in GW veterans related to war-related neurotoxicant exposures.

Hormonal changes in veterans with Gulf War Illness

AIMS

Gulf War Illness (GWI) is a multi-system condition of complex etiology and pathophysiology without specific treatment. There is an overlap between the symptoms of GWI and endocrinopathies. This study aimed to identify hormonal alterations in 1990-91 Gulf War (GW) veterans and the relationship between GWI and hormonal dysregulation.

MAIN METHODS

Data from 81 GW veterans (54 with GWI and 27 controls without GWI) was analyzed in a cross-sectional, case-control observational study. Participants completed multiple questionnaires, neuropsychiatric assessments, and a comprehensive set of hormone assays including a glucagon stimulation test (GST) for adult growth hormone deficiency (AGHD) and a high-dose adrenocorticotropic hormone (ACTH) stimulation test for adrenal insufficiency.

KEY FINDINGS

The GWI group had lower quality of life and greater severity of all symptoms compared to controls. Pain intensity and pain-related interference with general activity were also higher in the GWI group. AGHD was observed in 18 of 51 veterans with GWI (35.3 %) and 2 of 26 veterans without GWI (7.7 %) (p = 0.012 for interaction). Veterans with GWI also exhibited reduced insulin-like growth factor 1 (IGF-1) levels and IGF-1 Z-scores compared to controls. One participant with GWI met the criteria for adrenal insufficiency. No significant changes were observed in other hormonal axes.

SIGNIFICANCE

The frequency of AGHD was significantly higher in veterans with GWI compared to controls. Recombinant human growth hormone replacement therapy (GHRT) may become a breakthrough therapeutic option for this subgroup. A large clinical trial is needed to evaluate the efficacy of GHRT in patients with GWI and AGHD.

Dysbiosis in gastrointestinal pathophysiology: Role of the gut microbiome in Gulf War Illness

Gulf War Illness (GWI) has been reported in 25%-35% of veterans returned from the Gulf war. Symptoms of GWI are varied and include both neurological and gastrointestinal symptoms as well as chronic fatigue. Development of GWI has been associated with chemical exposure particularly with exposure to pyridostigmine bromide (PB) and permethrin. Recent studies have found that the pathology of GWI is connected to changes in the gut microbiota, that is the gut dysbiosis. In studies using animal models, the exposure to PB and permethrin resulted in similar changes in the gut microbiome as these found in GW veterans with GWI. Studies using animal models have also shown that phytochemicals like curcumin are beneficial in reducing the symptoms and that the extracellular vesicles (EV) released from gut bacteria and from the intestinal epithelium can both promote diseases and suppress diseases through the intercellular communication mechanisms. The intestinal epithelium cells produce EVs and these EVs of intestinal epithelium origin are found to suppress inflammatory bowel disease severity, suggesting the benefits of utilizing EV in treatments. On the contrary, EV from the plasma of septic mice enhanced the level of proinflammatory cytokines in vitro and neutrophils and macrophages in vivo, suggesting differences in the EV depending on the types of cells they were originated and/or influences of environmental changes. These studies suggest that targeting the EV that specifically have positive influences may become a new therapeutic strategy in the treatment of veterans with GWI.

Association of Gulf War Illness with Characteristics in Deployed vs. Non-Deployed Gulf War Era Veterans in the Cooperative Studies Program 2006/Million Veteran Program 029 Cohort: A Cross-Sectional Analysis

Gulf War Illness (GWI), a chronic multisymptom illness with a complex and uncertain etiology and pathophysiology, is highly prevalent among veterans deployed to the 1990-1991 GW. We examined how GWI phenotypes varied by demographic and military characteristics among GW-era veterans. Data were from the VA's Cooperative Studies Program 2006/Million Veteran Program (MVP) 029 cohort, Genomics of GWI. From June 2018 to March 2019, 109,976 MVP enrollees (out of a total of over 676,000) were contacted to participate in the 1990-1991 GW-era Survey. Of 109,976 eligible participants, 45,169 (41.1%) responded to the 2018-2019 survey, 35,902 respondents met study inclusion criteria, 13,107 deployed to the GW theater. GWI phenotypes were derived from Kansas (KS) and Centers for Disease Control and Prevention (CDC) GWI definitions: (a) KS Symptoms (KS Sym+), (b) KS GWI (met symptom criteria and without exclusionary health conditions) [KS GWI: Sym+/Dx-], (c) CDC GWI and (d) CDC GWI Severe. The prevalence of each phenotype was 67.1% KS Sym+, 21.5% KS Sym+/Dx-, 81.1% CDC GWI, and 18.6% CDC GWI severe. These findings affirm the persistent presence of GWI among GW veterans providing a foundation for further exploration of biological and environmental underpinnings of this condition.

Correlates and clinical associations of military sexual assault in Gulf War era U.S. veterans: Findings from a national sample

Military sexual assault (MSA) is a prevalent issue among military personnel that can have direct implications on postmilitary mental health. Gulf War era U.S. veterans represent the first cohort in which women veterans were integrated into most aspects of military service except for combat. The present study sought to build on prior studies by identifying characteristics associated with the occurrence of MSA and clinical correlates of MSA and examining how these differ between men and women. This study analyzed cross-sectional survey data from a national sample of treatment-seeking Gulf War era veterans. Participants (N = 1,153) reported demographic information, clinical outcomes, military background, and history of MSA. MSA was more common among female veterans (n = 100, 41.3%) than male veterans (n = 32, 3.6%). The odds of experiencing MSA were approximately 19 times higher for female veterans relative to their male peers, OR = 18.92, p < .001. Moreover, as expected, MSA was robustly associated with probable current posttraumatic stress disorder, probable current depression, and past-year suicidal ideation in female veterans, whereas combat exposure was robustly associated with these sequelae in male veterans. The present findings confirm that a large proportion of female veterans from the Gulf War era experienced MSA and highlight the deleterious correlates of MSA on veterans' mental health. Sex differences of correlates of MSA and subsequent clinical associations are highlighted.

The impact of neurotoxicant exposures on posttraumatic stress disorder trajectories: The Ft. Devens Gulf War Veterans Cohort

Gulf War veterans (GWVs) were exposed to neurotoxicants, including sarin nerve gas, anti-nerve agent pills, pesticides, oil well fires, and fumes from unvented tent heaters, all of which have been associated with subsequent adverse health. Posttraumatic stress disorder (PTSD) symptoms have also been associated with GW deployment; however, associations between exposures and PTSD symptoms have not been investigated. We assessed PTSD symptom trajectories and associations with neurotoxicant exposures in Ft. Devens Cohort (FDC) veterans (N = 259) who endorsed trauma exposure during deployment and completed the PTSD Checklist at three follow-ups (1992-1993, 1997-1998, 2013-2017). Results indicate that among veterans with more severe initial PTSD symptoms, symptoms remained significantly higher across follow-ups, Bs = -1.489-1.028, whereas among those with low initial PTSD symptoms, symptom severity increased significantly over time, Bs = 1.043-10.304. Additionally, neurotoxicant exposure was associated with a significant increase in PTSD symptoms, Bs = -1.870-9.003. Significant interactions between time and exposures were observed for PTSD symptom clusters, suggesting that among participants with high initial PTSD symptom, unexposed veterans experienced symptom alleviation, whereas exposed veterans' PTSD symptoms remained high. In GWVs with low initial PTSD symptoms, both unexposed and exposed veterans experienced PTSD symptom exacerbations over time; however, this occurred at a faster rate among exposed veterans. These findings suggest that in the years following deployment, GWVs who were exposed to both traumatic events and neurotoxicants may experience more severe and chronic PTSD symptoms than those without neurotoxicant exposures.

Association of Gulf War Illness-Related Symptoms with Military Exposures among 1990-1991 Gulf War Veterans Evaluated at the War-Related Illness and Injury Study Center (WRIISC)

Veterans with difficult-to-diagnose conditions who receive care in the Department of Veterans Affairs (VA) healthcare system can be referred for evaluation at one of three specialty VA War-Related Illness and Injury Study Centers (WRIISC). Veterans of the 1990−1991 Gulf War have long experienced excess rates of chronic symptoms associated with the condition known as Gulf War Illness (GWI), with hundreds evaluated at the WRIISC. Here we provide the first report from a cohort of 608 Gulf War Veterans seen at the WRIISC who completed questionnaires on chronic symptoms (>6 months) consistent with GWI as well as prominent exposures during Gulf War deployment. These included veterans’ reports of hearing chemical alarms/donning Military-Ordered Protective Posture Level 4 (MOPP4) gear, pesticide use, and use of pyridostigmine bromide (PB) pills as prophylaxis against the effects of nerve agents. Overall, veterans in the cohort were highly symptomatic and reported a high degree of exposures. In multivariable models, these exposures were significantly associated with moderate-to-severe chronic symptoms in neurocognitive/mood, fatigue/sleep, and pain domains. Specifically, exposure to pesticides was associated with problems with concentration and memory, problems sleeping, unrefreshing sleep, and joint pain. Use of MOPP4 was associated with light sensitivity and unrefreshing sleep and use of PB was associated with depression. We also evaluated the association of exposures with symptom summary scores based on veterans’ severity of symptoms in four domains and overall. In multivariable modeling, the pain symptom severity score was significantly associated with pesticide use (Odds ratio (OR): 4.13, 95% confidence intervals (CI): 1.78−9.57) and taking PB pills (OR: 2.28, 95% CI: 1.02−5.09), and overall symptom severity was significantly associated with use of PB pills (OR: 2.41, 95% CI: 1.01−5.75). Conclusion: Decades after deployment, Gulf War veterans referred to a VA tertiary evaluation center report a high burden of chronic symptoms, many of which were associated with reported neurotoxicant exposures during the war.

Health symptom trajectories and neurotoxicant exposures in Gulf War veterans: the Ft. Devens cohort

BACKGROUND

Thirty years ago, Gulf War (GW) veterans returned home with numerous health symptoms that have been associated with neurotoxicant exposures experienced during deployment. The health effects from these exposures have been termed toxic wounds. Most GW exposure-outcome studies utilize group analyses and thus individual fluctuations in symptoms may have been masked. This study investigates health symptom trajectories in the same veterans over 25 years.

METHODS

Veterans were categorized into 5 a priori trajectory groups for each health symptom and Chronic Multisymptom Illness (CMI) clinical case status. Multinomial logistic regression models were used to investigate associations between these trajectories and neurotoxicant exposures.

RESULTS

Results indicate that more than 21 Pyridostigmine Bromide (PB) pill exposure was associated with consistent reporting of fatigue, pain, and cognitive/mood symptoms as well as the development of six additional symptoms over time. Chemical weapons exposure was associated with both consistent reporting and development of neurological symptoms over time. Reported exposure to tent heater exhaust was associated with later development of gastrointestinal and pulmonary symptoms. Veterans reporting exposure to more than 21 PB pills were more than 8 times as likely to consistently meet the criteria for CMI over time.

CONCLUSION

This study highlights the importance of the continued documentation of the health impacts experienced by GW veterans', their resulting chronic health symptoms, and the importance of exposure-outcome relationships in these veterans now 30 years post-deployment.

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.

The association of pre-war medical conditions to Gulf War Illness

AIMS

Gulf War Illness (GWI) remains a significant health concern for many veterans. The relation of pre-war health conditions and symptoms to GWI could aid in developing a more accurate case definition of GWI. The objective of this study was to investigate pre-war predictors of GWI in a population-based sample of Gulf War veterans using two definitions of GWI.

MAIN METHODS

Data come from the 1995-1997 National Health Survey of Persian Gulf War Era Veterans, a survey of a representative sample of deployed and non-deployed US veterans. Using two definitions of GWI (CDC/Kansas and a newly developed 3-domain definition), we conducted a series of multivariable logistic regression analyses to assess the associations of demographic, lifestyle factors, and pre-war medical conditions and symptoms to subsequent GWI.

KEY FINDINGS

All pre-war symptom predictor domains were significantly and positively associated with GWI using a new 3-domain definition with aORs for individual domains ranging from 2.17 (95% CI = 1.99-2.38) for dermatologic conditions to 3.06 (95% CI = 2.78-3.37) for neurological conditions. All symptom predictor domains were associated with significantly increased likelihood of GWI using the CDC/Kansas definition, with aORs ranging from 2.54 (95% CI = 2.31-2.81) for inflammatory conditions to 3.22 (95% CI = 2.94-3.55) for neurological conditions. These estimates were attenuated but remained significant after inclusion of all significant symptom predictor domains.

SIGNIFICANCE

Results from this study suggest that demographic/lifestyle factors and pre-war medical conditions are strong predictors of GWI. Additional research is needed to confirm these findings, and to clarify the unique characteristics of this common, but still poorly understood illness.

Genomics of Gulf War Illness in U.S. Veterans Who Served during the 1990-1991 Persian Gulf War: Methods and Rationale for Veterans Affairs Cooperative Study #2006

Background: Approximately 697,000 members of the U.S. Armed Forces were deployed to the Persian Gulf in support of the 1990–1991 Persian Gulf War (GW). Subsequently, many deployed and some non-deployed veterans developed a chronic multi-symptom illness, now named Gulf War Illness (GWI). This manuscript outlines the methods and rationale for studying the genomics of GWI within the Million Veteran Program (MVP), a VA-based national research program that has linked medical records, surveys, and genomic data, enabling genome-wide association studies (GWASs). Methods: MVP participants who served in the military during the GW era were contacted by mail and invited to participate in the GWI study. A structured health questionnaire, based on a previously tested instrument, was also included in the mailing. Data on deployment locations and exposures, symptoms associated with GWI, clinical diagnoses, personal habits, and health care utilization were collected. Self-reported data will be augmented with chart reviews and structured international classification of disease codes, to classify participants by GWI case status. We will develop a phenotyping algorithm, based on two commonly used case definitions, to determine GWI status, and then conduct a nested case-control GWAS. Genetic variants associated with GWI will be investigated, and gene–gene and gene–environment interactions studied. The genetic overlap of GWI with, and causative mechanisms linking this illness to, other health conditions and the effects of genomic regulatory mechanisms on GWI risk will also be explored. Conclusions: The proposed initial GWAS described in this report will investigate the genomic underpinnings of GWI with a large sample size and state-of-the-art genomic analyses and phenotyping. The data generated will provide a rich and expansive foundation on which to build additional analyses.

A review of pre-clinical models for Gulf War Illness

Gulf War Illness (GWI) is a chronic multisymptomatic disorder that afflicts over 1/3rd of the 1991 GW veterans. It spans multiple bodily systems and presents itself as a syndrome exhibiting diverse symptoms including fatigue, depression, mood, and memory and concentration deficits, musculoskeletal pain and gastrointestinal distress in GW veterans. The etiology of GWI is complex and many factors, including chemical, physiological, and environmental stressors present in the GW arena, have been implicated for its development. It has been over 30 years since the end of the GW but, GWI has been persistent in suffering veterans who are also dealing with paucity of effective treatments. The multifactorial aspect of GWI along with genetic heterogeneity and lack of available data surrounding war-time exposures have proved to be challenging in developing pre-clinical models of GWI. Despite this, over a dozen GWI animal models exist in the literature. In this article, following a brief discussion of GW history, GWI definitions, and probable causes for its pathogenesis, we will expand upon various experimental models used in GWI laboratory research. These animal models will be discussed in the context of their attempts at mimicking GW-related exposures with regards to the variations in chemical combinations, doses, and frequency of exposures. We will discuss their advantages and limitations in modeling GWI followed by a discussion of behavioral and molecular findings in these models. The mechanistic data obtained from these preclinical studies have offered multiple molecular pathways including chronic inflammation, mitochondrial dysfunction, oxidative stress, lipid disturbances, calcium homeostatic alterations, changes in gut microbiota, and epigenetic modifications, amongst others for explaining GWI development and its persistence. Finally, these findings have also informed us on novel druggable targets in GWI. While, it has been difficult to conceive a single pre-clinical model that could express all the GWI signs and exhibit biological complexity reflective of the clinical presentation in GWI, animal models have been critical for identifying molecular underpinnings of GWI and evaluating treatment strategies for GWI.

The effect of stress on the transcriptomes of circulating immune cells in patients with Gulf War Illness

AIMS

In an effort to gain further insight into the underlying mechanisms tied to disease onset and progression of Gulf War Illness (GWI), our team evaluated GWI patient response to stress utilizing RNA-Seq.

MAIN METHODS

The protocol included blood collection before exercise challenge (baseline), at maximal exertion, and after exercise challenge (recovery - four hours post-exercise challenge). Peripheral blood mononuclear cell (PBMC) transcriptomics data were analyzed to understand why GWI patients process stressors differently from their healthy counterparts.

KEY FINDINGS

Our findings validate previously identified dysregulation of immune and inflammatory pathways among GWI patients as well as highlight novel immune and inflammatory markers of disease activity. These results provide a foundation for future research efforts in understanding GWI pathophysiology and creating targeted treatments.

SIGNIFICANCE

Gulf War Illness is a complex, chronic, and debilitating multi-system illness impacting 25%-30% of the U.S. troops deployed to the 1990-1991 Gulf War. The condition is characterized by medically unexplained fatigue and affects multiple organ systems. Because the underlying mechanisms are largely unknown, patients receive symptom-based treatment, rather than targeting fundamental biological processes. To the best of our knowledge, this is the first study that applies RNA-Seq to analyze the effect of GWI, and the response to stressors in GWI, on the transcriptomic changes in circulating immune cells.

Neurotoxicant exposures and rates of Chronic Multisymptom Illness and Kansas Gulf War Illness criteria in Gulf War deployed women veterans

AIMS

This study analyzed deployment-related exposures and risk of Persian Gulf War Illness (GWI) in women veterans from the Veterans Affairs (VA) Cooperative Studies Program 585 Gulf War Era Cohort and Biorepository (GWECB CSP#585).

MAIN METHODS

We examined the associations between GW deployment-related exposures and case definitions for GWI in deployed GW women. Multivariate regression analyses controlling for demographic outcomes were performed.

KEY FINDINGS

Surveys were obtained from 202 GW deployed women veterans. Self-reported exposure to smoke from oil well fires as well as chemical and biological warfare were the only exposures significantly associated with the Center for Disease Control and Prevention (CDC) GWI criteria. Seventy-nine women were excluded from the rest of the analyses as they met Kansas GW illness exclusion criteria. Eligible women who self-reported deployment-related exposure to smoke from oil wells, pyridostigmine bromide (PB) pills, pesticide cream, pesticide treated uniforms, and insect baits were significantly more likely to meet the Kansas GWI criteria (n = 123) than those unexposed and exposures were related to Kansas symptom subdomain endorsements.

SIGNIFICANCE

These results suggest that women GW veterans reporting deployment related exposures of pesticide, oil well fire and PB pills are significantly more likely to meet the Kansas GWI criteria in this national cohort of GW women suggesting its utility in future studies. In addition, based on these results it appears that women exposed to particular toxicants during the war may benefit from more targeted treatment strategies dependent upon the mechanism of exposure of their toxicant induced outcomes.

Emerging role of glutamate in the pathophysiology and therapeutics of Gulf War illness

Gulf War illness (GWI) is a chronic and multi-symptomatic disorder affecting veterans who served in the Gulf War. The commonly reported symptoms in GWI veterans include mood problems, cognitive impairment, muscle and joint pain, migraine/headache, chronic fatigue, gastrointestinal complaints, skin rashes, and respiratory problems. Neuroimaging studies have revealed significant brain structure alterations in GWI veterans, including subcortical atrophy, decreased volume of the hippocampus, reduced total grey and white matter, and increased brain white matter axial diffusivity. These brain changes may contribute to or increase the severities of the GWI-related symptoms. Epidemiological studies have revealed that neurotoxic exposures and stress may be significant contributors to the development of GWI. However, the mechanism underlying how the exposure and stress could contribute to the multi-symptomatic disorder of GWI remains unclear. We and others have demonstrated that rodent models exposed to GW-related agents and stress exhibited higher extracellular glutamate levels, as well as impaired structure and function of glutamatergic synapses. Restoration of the glutamatergic synapses ameliorated the GWI-related pathological and behavioral deficits. Moreover, recent studies showed that a low-glutamate diet reduced multiple symptoms in GWI veterans, suggesting an important role of the glutamatergic system in GWI. Currently, growing evidence has indicated that abnormal glutamate neurotransmission may contribute to the GWI symptoms. This review summarizes the potential roles of glutamate dyshomeostasis and dysfunction of the glutamatergic system in linking the initial cause to the multi-symptomatic outcomes in GWI and suggests the glutamatergic system as a therapeutic target for GWI.

Gulf War illness in the Gulf War Era Cohort and Biorepository: The Kansas and Centers for Disease Control definitions

AIMS

This study characterizes Gulf War Illness (GWI) among U.S. veterans who participated in the Gulf War Era Cohort and Biorepository (GWECB).

MAIN METHODS

Mailed questionnaires were collected between 2014 and 2016. Self-reported GWI symptoms, symptom domain criteria, exclusionary diagnoses, and case status were examined based on the originally published Kansas and Centers for Disease Control (CDC) definitions in the GWECB cohort (n = 849 deployed to Gulf and n = 267 non-deployed). Associations among GWI and deployment status, demographic, and military service characteristics were examined using logistic regression.

KEY FINDINGS

Among deployed veterans in our sample, 39.9% met the Kansas criteria and 84.2% met the CDC criteria for GWI. Relative to non-deployed veterans, deployed veterans had a higher odds of meeting four GWI case status-related measures including the Kansas symptom criteria (aOR = 2.05, 95% CI = 1.50, 2.80), Kansas GWI case status (aOR = 1.42, 95% CI = 1.05, 1.93), the CDC GWI case status (aOR = 1.57, 95% CI = 1.07, 2.29) and the CDC severe criteria (aOR = 2.67, 95% CI = 1.79, 3.99). Forty percent met the Kansas exclusionary criteria, with no difference by deployment status. Some symptoms were nearly universally endorsed.

SIGNIFICANCE

This analysis provides evidence of a sustained, multisymptom illness in veterans who deployed to the Persian Gulf War compared to non-deployed Gulf War era veterans nearly 25 years later. Differences in symptoms attributed to GWI by deployment status have diminished since initial reports, suggesting the need to update GWI definitions to account for aging-related conditions and symptoms. This study provides a foundation for future efforts to establish a single GWI case definition and analyses that employ the biorepository.

Sex-Based Differences in Plasma Autoantibodies to Central Nervous System Proteins in Gulf War Veterans versus Healthy and Symptomatic Controls

Veterans from the 1991 Gulf War (GW) have suffered from Gulf War illness (GWI) for nearly 30 years. This illness encompasses multiple body systems, including the central nervous system (CNS). Diagnosis and treatment of GWI is difficult because there has not been an objective diagnostic biomarker. Recently, we reported on a newly developed blood biomarker that discriminates GWI from GW healthy controls, and symptomatic controls with irritable bowel syndrome (IBS) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The present study was designed to compare levels of these biomarkers between men and women with GWI, as well as sex-specific effects in comparison to healthy GW veterans and symptomatic controls (IBS, ME/CFS). The results showed that men and women with GWI differ in 2 of 10 plasma autoantibodies, with men showing significantly elevated levels. Men and women with GWI showed significantly different levels of autoantibodies in 8 of 10 biomarkers to neuronal and glial proteins in plasma relative to controls. In summary, the present study addressed the utility of the use of plasma autoantibodies for CNS proteins to distinguish among both men and women veterans with GWI and other healthy and symptomatic control groups.

Pyridostigmine bromide exposure creates chronic, underlying neuroimmune disruption in the gastrointestinal tract and brain that alters responses to palmitoylethanolamide in a mouse model of Gulf War Illness

Gulf War Illness (GWI) is a chronic multisymptom illness that includes gastrointestinal disorders. Although the exact etiology of GWI is unknown, exposure to the drug pyridostigmine bromide (PB) is considered a major factor. Exposure to PB drives enteric neuroinflammation, promotes immunosuppression, and alters physiological functions of the colon in the short term but whether exposure to PB is sufficient to promote long term dysfunction is not known. Here, we tested whether exposure to PB is sufficient to drive long term changes that reflect GWI, and whether the endogenous anti-inflammatory mediator palmitoylethanolamide (PEA) is sufficient to reduce the detrimental effects of PB in the gut and brain of mice. Exposure to PB alone was not sufficient to cause major changes in neuromuscular transmission but did drive major changes by altering the effects of PEA. Calcium imaging data show that the mechanisms responsible include a shift in receptor signaling mediated by TRPV1, endocannabinoids, and peroxisome proliferator-activated receptors alpha (PPARα). Additional mechanisms include the development of glial reactivity and changes in enteric neurochemical coding and survival. PB and PEA caused major shifts in pro-inflammatory cytokines/chemokines in the brain and colon that persisted up to 5 months following exposure. Many of the effects of PB and PEA exhibit significant sex differences. Together, these results highlight novel mechanisms whereby PB promotes long-lasting changes in nervous system and immune function by inducing occult neuroplasticity that is revealed by subsequent exposure to unrelated drugs in a sex dependent manner.

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.

Changes in Health Status in the Ft. Devens Gulf War Veterans Cohort: 1997-2017

Gulf War veterans (GWVs) were exposed to numerous neurotoxicants during deployment. Upon returning home, many reported a multitude of symptoms including fatigue, pain, gastrointestinal and respiratory issues, and neurological, cognitive, and mood complaints, collectively termed "Gulf War Illness (GWI)." Now, nearly 30 years post-war, many GWVs continue to suffer from these symptoms, in addition to health concerns associated with normal aging. While most research on GWVs has been cross-sectional, it is important to evaluate the progression and onset of new GWI symptoms longitudinally. The current study investigated the health of GWVs 25+ years after the war by resurveying the Ft. Devens Cohort and comparing their current health to their health reported 15 to 20 years earlier. The sample consists of 317 GWVs (~54 years old at the latest survey, 38 women) who responded to both surveys (1997-1998 and 2013-2017). Multivariable regression analyses were used to assess changes in GWI symptomatology and prevalence of medical conditions. The rates of 12 of 25 health symptoms increased significantly from the prior 1997-1998 survey. Anxiety, numbness in extremities, depressed mood, and joint pain had the greatest increase in endorsement. The rates of 7 of 16 medical conditions increased significantly from the prior 1997-1998 survey. High blood pressure, diabetes, and cancer had the greatest increase in prevalence. In summary, this study demonstrates that both symptoms and physician-diagnosed medical conditions associated with GW deployment/exposure increased in prevalence. For GWVs, focus by providers on the treatment of cognitive and mental health issues as well as cardiovascular and cerebrovascular risk factors is warranted. Targeting symptom alleviation would help improve the quality of life in these veterans until treatments addressing the entire illness become available.

Acetylcholinesterase inhibitor exposures as an initiating factor in the development of Gulf War Illness, a chronic neuroimmune disorder in deployed veterans

Gulf War Illness (GWI) is a chronic multi-symptom disorder, characterized by symptoms such as fatigue, pain, cognitive and memory impairment, respiratory, skin and gastrointestinal problems, that is experienced by approximately one-third of 1991 Gulf War veterans. Over the nearly three decades since the end of the war, investigators have worked to elucidate the initiating factors and underlying causes of GWI. A significant portion of this research has indicated a strong correlation between GWI and exposure to a number of different acetycholinesterase inhibitors (AChEIs) in theater, such as sarin and cyclosarin nerve agents, chlorpyrifos and dichlorvos pesticides, and the anti-nerve agent prophylactic pyridostigmine bromide. Through studying these exposures and their relationship to the symptoms presented by ill veterans, it has become increasingly apparent that GWI is the likely result of an underlying neuroimmune disorder. While evidence indicates that AChEIs are a key exposure in the development of GWI, particularly organophosphate AChEIs, the mechanism(s) by which these chemicals instigate illness appears to be related to "off-target", non-cholinergic effects. In this review, we will discuss the role of AChEI exposure in the development and persistence of GWI; in particular, how these chemicals, combined with other exposures, have led to a chronic neuroimmune disorder. This article is part of the special issue entitled 'Acetylcholinesterase Inhibitors: From Bench to Bedside to Battlefield'.

The Gulf War Women's Health Cohort: Study Design and Protocol

Military service and deployment affect women differently than men, underscoring the need for studies of the health of women veterans and their receipt of health care services. Despite the large numbers of women who served during the 1990-1991 Gulf War, few studies have evaluated Gulf War illness (GWI) and other medical conditions specifically as they affect women veterans of the 1991 Gulf War. The objectives of the Gulf War Women's Health Cohort study are: (1) to establish the Gulf War women's cohort (GWWC), a large sample of women veterans who served in the 1990-1991 Gulf War and a comparison group of women who served in other locations during that period; and (2) to provide current, comprehensive data on the health status of women who served during the 1990-1991 Gulf War, and identify any specific conditions that affect Gulf War women veterans at excess rates. The study will utilize both existing datasets and newly collected data to examine the prevalence and patterns of Gulf War Illness symptoms, diagnosed medical conditions, reproductive health, birth outcomes and other health issues among women who served during the Gulf War. The Gulf War Women's Health Cohort study will address the need for information about the comprehensive health of women veterans who were deployed to the Gulf War, and other wars during the Gulf War era.

Gender-based Differences among 1990-1991 Gulf War Era Veterans: Demographics, Lifestyle Behaviors, and Health Conditions

OBJECTIVE

The 1990-1991 Gulf War employed more women servicemembers than any prior conflict. Gender-based differences among veterans of this era have yet to be explored. This study is among the first and most recent to stratify Gulf War veteran demographics, lifestyle factors, and self-reported diagnoses by gender.

METHODS

Data from the cross-sectional Gulf War Era Cohort and Biorepository pilot study (n = 1,318; collected between 2014 and 2016), including users and nonusers of the Veterans Health Administration, were used to calculate demographics and adjusted odds ratios.

RESULTS

Women veterans were oversampled and comprised approximately 23% of the sample. Women reported similar rates of Veterans Health Administration use (44%) and deployment (67%) as men (46% and 72%, respectively). Women were less likely than men to report frequent alcohol use (adjusted odds ratio [aOR], 0.59; 95% confidence interval [CI], 0.43-0.81; p = .0009) or have a history of smoking (aOR, 0.65; 95% CI, 0.49-0.84; p = .0014). Among common health conditions, women were more likely than men to report a diagnosis of osteoporosis (aOR, 4.24; 95% CI, 2.39-7.51; p < .0001), bipolar disorder (aOR, 2.15; 95% CI, 1.15-4.04; p = .0167), depression (aOR, 2.39; 95% CI, 1.81-3.16; p < .0001), irritable bowel syndrome (aOR, 2.10; 95% CI, 1.43-3.09; p = .0002), migraines (aOR, 2.96; 95% CI, 2.18-4.01; p < .0001), asthma (aOR, 1.86; 95% CI, 1.29-2.67; p = .0008), and thyroid problems (aOR, 4.60; 95% CI, 3.14-6.73; p < .0001). Women were less likely than men to report hypertension (aOR, 0.55; 95% CI, 0.41-0.72; p < .0001), tinnitus (aOR, 0.46; 95% CI, 0.33-0.63; p < .0001), and diabetes (aOR, 0.44; 95% CI, 0.28-0.69; p = .0003).

CONCLUSIONS

Health differences exist between female and male veterans from the 1990-1991 Gulf War. Gender-specific analyses are needed to better understand the unique health care needs of Gulf War Era veterans and direct future research.

Oligodendrocyte involvement in Gulf War Illness

Low level sarin nerve gas and other anti‐cholinesterase agents have been implicated in Gulf War illness (GWI), a chronic multi‐symptom disorder characterized by cognitive, pain and fatigue symptoms that continues to afflict roughly 32% of veterans from the 1990–1991 Gulf War. How disrupting cholinergic synaptic transmission could produce chronic illness is unclear, but recent research indicates that acetylcholine also mediates communication between axons and oligodendrocytes. Here we investigated the hypothesis that oligodendrocyte development is disrupted by Gulf War agents, by experiments using the sarin‐surrogate acetylcholinesterase inhibitor, diisopropyl fluorophosphate (DFP). The effects of corticosterone, which is used in some GWI animal models, were also investigated. The data show that DFP decreased both the number of mature and dividing oligodendrocytes in the rat prefrontal cortex (PFC), but differences were found between PFC and corpus callosum. The differences seen between the PFC and corpus callosum likely reflect the higher percentage of proliferating oligodendroglia in the adult PFC. In cell culture, DFP also decreased oligodendrocyte survival through a non‐cholinergic mechanism. Corticosterone promoted maturation of oligodendrocytes, and when used in combination with DFP it had protective effects by increasing the pool of mature oligodendrocytes and decreasing proliferation. Cell culture studies indicate direct effects of both DFP and corticosterone on OPCs, and by comparison with in vivo results, we conclude that in addition to direct effects, systemic effects and interruption of neuron–glia interactions contribute to the detrimental effects of GW agents on oligodendrocytes. Our results demonstrate that oligodendrocytes are an important component of the pathophysiology of GWI.

Medical Correlates of Chronic Multisymptom Illness in Gulf War Veterans

BACKGROUND

Chronic multisymptom illness (CMI) is more prevalent among deployed than nondeployed veterans from the first Gulf War. Objective physiologic markers of CMI are lacking. The purpose of this study is to determine whether measurable abnormalities in the autonomic nervous system or hypothalamic-pituitary adrenal axis would distinguish CMI cases (CMI+) from controls (CMI-) among deployed veterans of the 1990-1991 Gulf War.

METHODS

This is a cross-sectional case-control cohort study that examined deployed veterans who participated in the Phase III study: National Health Survey of Gulf War Veterans and Their Families. Autonomic nervous system and hypothalamic-pituitary adrenal axis function-related measures included: 24-hour heart-rate variability, urinary catecholamines and cortisol, hypertension, insulin sensitivity, dyslipidemia, body fat, bone mineral density, and ultrasensitive C-reactive protein.

RESULTS

Veterans of the first Gulf War with CMI (n = 73) and without the condition (n = 111) were studied. Sociodemographic characteristics were similar. Veterans with CMI reported poorer mental and physical functioning, greater use of prescription medications, and more nonroutine clinic visits. These veterans were also more likely to have fibromyalgia syndrome, irritable bowel syndrome, metabolic syndrome, and among males, a larger waist-to-hip ratio. Lower values for a nonlinear heart-rate-variability parameter-the short-term fractal scaling exponent (DFA1), reflecting an increased randomness of beat-to-beat changes in heart rate-were observed in veterans with CMI than those veterans without it (1.28±0.16vs 1.35±0.15; p=0.005). Hypothalamic-pituitary-adrenal axis function measures were similar between the two groups.

CONCLUSION

In this cohort of deployed veterans from the first Gulf War, we identified abnormal heart-rate variability in veterans with CMI compared to veterans without the condition, which suggests abnormal functioning of the autonomic nervous system and possible long-term cardiovascular effects.

Rates of Chronic Medical Conditions in 1991 Gulf War Veterans Compared to the General Population

Prevalence of nine chronic medical conditions in the population-based Ft. Devens Cohort (FDC) of GW veterans were compared with the population-based 2013–2014 National Health and Nutrition Examination Survey (NHANES) cohort. Excess prevalence was calculated as the difference in prevalence estimates from the Ft. Devens and NHANES cohorts; and confidence intervals and p-values are based on the standard errors for the two prevalence estimates. FDC males were at increased risk for reporting seven chronic medical conditions compared with NHANES males. FDC females were at decreased risk for high blood pressure and increased risk for diabetes when compared with NHANES females. FDC veterans reporting war-related chemical weapons exposure showed higher risk of high blood pressure; diabetes; arthritis and chronic bronchitis while those reporting taking anti-nerve gas pills had increased risk of heart attack and diabetes. GW veterans are at higher risk of chronic conditions than the general population and these risks are associated with self-reported toxicant exposures.

Gastrointestinal neuroimmune disruption in a mouse model of Gulf War illness

Gulf War illness (GWI) is a chronic multisymptom disorder that is prominent in Gulf War veterans. Major unexplained symptoms of GWI include functional gastrointestinal disorders and undiagnosed illnesses, including neurologic disorders. Exposure to the antinerve gas drug pyridostigmine bromide (PB) is linked to the development of GWI, but the exact mechanisms remain unclear. Here, we tested the hypothesis that PB alters gut function by disrupting the neural and immune systems of the intestine. We exposed male and female mice to physiologically comparable amounts of PB that match the dose, route, and time frame of exposure experienced by Gulf War veterans and assessed the acute and chronic impacts on gastrointestinal functions, the functional architecture of the enteric nervous system, and immune responses in the gut and brain. Exposure to PB drove acute alterations to colonic motility and structure in both male and female mice that transitioned to chronic changes in gut functions. PB drove acute alterations to enteric neural and glial activity, glial reactivity, and neuron survival with glial reactivity persisting into the chronic phase in male mice. Despite having no effect on colonic permeability, exposure to PB caused major shifts in the expression of proinflammatory cytokines and chemokines in the colon and brain that suggest immunosuppressive effects. Interestingly, immune disruption was still evident in the colon and brain in female animals at 1 mo following exposure to PB. Together, our results show that the paradigm of PB exposure experienced by veterans of the Persian Gulf War contributes to long-lasting pathophysiology by driving enteric neuroinflammation, promoting immunosuppression, and altering functional anatomy of the colon in a sex-dependent manner.-Hernandez, S., Fried, D. E., Grubišić, V., McClain, J. L., Gulbransen, B. D. Gastrointestinal neuroimmune disruption in a mouse model of Gulf War illness.

The Multiple Hit Hypothesis for Gulf War Illness: Self-Reported Chemical/Biological Weapons Exposure and Mild Traumatic Brain Injury

The Gulf War Illness Consortium (GWIC) was designed to identify objective biomarkers of Gulf War Illness (GWI) in 1991 Gulf War veterans. The symptoms of GWI include fatigue, pain, cognitive problems, gastrointestinal, respiratory, and skin problems. Neurotoxicant exposures during deployment, such as pesticides, sarin, and pyridostigmine bromide pills have been identified as contributors to GWI. We have also found an association between mild traumatic brain injury (mTBI) and increased rates of GWI. However, the combined impact of these physical and chemical exposures has not yet been explored in GWI. The objective of this study was to examine both self-reported mTBI and exposure to chemical/biological weapons (CBW) as a multiple or two hit model for increased risk of GWI and other chronic health conditions. The study population included 125 Gulf War (GW) veterans from the Boston GWIC. Exposure to CBW was reported in 47.2% of the study population, and 35.2% reported sustaining a mTBI during the war. Results confirmed that those with both exposures (mTBI and CBW) had higher rates of comorbid chronic health conditions while rates of GWI were equivalent for mTBI and CBW or mTBI alone. The timing of exposure to mTBI was found to be strikingly different between those with GWI and those without it. Correspondingly, 42.3% of GWI cases reported experiencing a mTBI during military service while none of the controls did (p = 0.0002). Rates of mTBI before and after the war did not differ between the cases and controls. In addition, 54% of cases compared to 14.3% of controls (p = <0.001) reported being exposed to CBW during military service. The current study examined the relation of the separate and combined effects of exposure to mTBI and CBW in 1991 GW veterans. The findings from this study suggest that both exposure to mTBI and CBW are associated with the development of GWI and multiple chronic health conditions and that combined exposure appears to lead to higher risk of chronic health effects.

The Gulf War Era Cohort and Biorepository: A Longitudinal Research Resource of Veterans of the 1990-1991 Gulf War Era

The US Department of Veterans Affairs (VA) Gulf War Era Cohort and Biorepository (GWECB) is a nationally representative longitudinal cohort of US veterans who served during the 1990-1991 Gulf War era. The GWECB combines survey data, such as demographic, health behavior, and environmental exposure data; medical records; and a linked biorepository of blood specimens that can support a broad range of future research regarding health concerns unique to veterans of this era. To build this resource, the VA Cooperative Studies Program initiated a pilot study (2014-2016) to establish the GWECB and evaluate the processes required to build and maintain the resource. Participants (n = 1,275) consented to future sharing of their data and biospecimens for research purposes. Here we describe the pilot study, including recruitment and enrollment procedures, data collection and management, quality control, and challenges experienced. The GWECB data available to investigators under approved sharing mechanisms and the procedures for accessing them are extensively detailed. The study's consenting documents and a website link for the research survey are provided. Our hope is that new research drawing on the GWECB data and biospecimens will result in effective treatments and improved approaches to address the health concerns of Gulf War-era veterans.

Meta-analysis of self-reported health symptoms in 1990-1991 Gulf War and Gulf War-era veterans

OBJECTIVES

Across diverse groups of Gulf War (GW) veterans, reports of musculoskeletal pain, cognitive dysfunction, unexplained fatigue, chronic diarrhoea, rashes and respiratory problems are common. GW illness is a condition resulting from GW service in veterans who report a combination of these symptoms. This study integrated the GW literature using meta-analytical methods to characterise the most frequently reported symptoms occurring among veterans who deployed to the 1990-1991 GW and to better understand the magnitude of ill health among GW-deployed veterans compared with non-deployed GW-era veterans.

DESIGN

Meta-analysis.

METHODS

Literature databases were searched for peer-reviewed studies published from January 1990 to May 2017 reporting health symptom frequencies in GW-deployed veterans and GW-era control veterans. Self-reported health symptom data were extracted from 21 published studies. A binomial-normal meta-analytical model was used to determine pooled prevalence of individual symptoms in GW-deployed veterans and GW-era control veterans and to calculate combined ORs of health symptoms comparing GW-deployed veterans and GW-era control veterans.

RESULTS

GW-deployed veterans had higher odds of reporting all 56 analysed symptoms compared with GW-era controls. Odds of reporting irritability (OR 3.21, 95% CI 2.28 to 4.52), feeling detached (OR 3.59, 95% CI 1.83 to 7.03), muscle weakness (OR 3.19, 95% CI 2.73 to 3.74), diarrhoea (OR 3.24, 95% CI 2.51 to 4.17) and rash (OR 3.18, 95% CI 2.47 to 4.09) were more than three times higher among GW-deployed veterans compared with GW-era controls.

CONCLUSIONS

The higher odds of reporting mood-cognition, fatigue, musculoskeletal, gastrointestinal and dermatological symptoms among GW-deployed veterans compared with GW-era controls indicates these symptoms are important when assessing GW veteran health status.

A Neuroimmune Model of Gulf War Illness

Several studies have implicated immune system disruption in the pathophysiology of GWI. In addition, alterations in brain structure and functioning have been associated with specific exposures in theater, including pyridostigmine bromide and nerve gas agents. Recent studies conducted up to 25 years after the 1991 conflict have examined factors associated with the continuation or worsening of GWI.

Drawing upon published studies of neural and immune system abnormalities in veterans with GWI, this paper proposes a model of GWI that takes into account neurologic and immunologic pathways, neuroimmune mechanisms of disease pathophysiology, individual predisposition due to sex and genetic background, and comorbid factors including neurological conditions such as neuritis/neuralgia and epilepsy that may occur along a continuum with GWI.

The proposed neuroimmune model of GWI is likely to be useful for designing new research studies, clarifying factors involved in the continuation or worsening of GWI, and identifying biomarker screening algorithms for the illness. The proposed model goes beyond previously proposed frameworks for GWI by taking into account potential differences in risk based upon female vs. male sex, time elapsed since exposure to neurotoxicants, duration and severity of illness, comorbid conditions, and genotype.

A Review of Epidemiologic Studies of the Health of Gulf War Women Veterans

INTRODUCTION

In the 25 years since the 1990-1991 Gulf War (GW), studies have evaluated Gulf War Illness (GWI), sometimes referred to as medically unexplained multi symptom illness, and other medical and neurological conditions in women GW veterans.

MATERIALS AND METHODS

In this article, we review epidemiologic studies of the health of women who served in the 1990-1991 GW based upon bibliographic searches in PubMed and CINAHL with relevant search terms through September 2015.

RESULTS

A total of 56 articles were identified in the bibliographic searches. By screening abstracts or full-text articles, a total of 21 relevant studies were identified. Results from some studies, but not all, suggest that GWI is more common in women GW veterans than their male counterparts. Few studies of GW veterans focused on women's health. A small number of studies suggested excess rates of woman's health problems, e.g., breast cysts, abnormal Papanicolaou (Pap) smears, yeast infections, and bladder infections. Several studies have identified significantly elevated rates of birth defects and adverse reproductive outcomes among GW veterans. However, findings have varied with different study designs and sample sizes, with some studies showing elevated risks of stillbirths, miscarriages, and/or birth defects and others have not. In some studies, participants reported increased risks of ectopic pregnancies and spontaneous abortions.

CONCLUSION

Further research is needed to provide a comprehensive picture of the health of women GW veterans and to examine a broad range of women's health issues including adverse reproductive outcomes. Some deployment-related health problems only become apparent decades later and other conditions may worsen or improve over time. Assessments are needed of current health status, changes in health symptoms and conditions over time, and possible differences in health outcomes associated with specific experiences and exposures during the war. Future studies would be strengthened by assessing GWI symptom patterns that may be specific to women veterans, examine diagnosed medical conditions among women veterans, and evaluate changes in women's health over time, including changes potentially associated with menopause and age.

Multiple Mild Traumatic Brain Injuries Are Associated with Increased Rates of Health Symptoms and Gulf War Illness in a Cohort of 1990-1991 Gulf War Veterans

Recent research demonstrated a relation between traumatic brain injury (TBI), health symptoms and diagnosis of Gulf War Illness (GWI) in Gulf War Veterans, but no study has examined the impact of multiple mild TBIs (mTBIs). A total of 229 male Gulf War Veterans from the Ft Devens Cohort were categorized by a number of mTBIs reported. One-way ANOVA and chi-square test of independence were used to test for differences in total reported health symptoms and diagnosis of chronic multisymptom illness (CMI) or Kansas GWI criteria, two of the most common case definitions of GWI. A total of 72 veterans reported no mTBIs (31.4%), 26 reported one mTBI (11.4%), 25 reported two mTBIs (10.9%), and 106 veterans reported sustaining three or more mTBIs (46.3%). Veterans reporting two or more mTBIs (p < 0.01) or three or more mTBIs (p < 0.001) endorsed significantly higher rates of health symptoms than Veterans reporting no mTBIs. Significantly higher rates of CMI (p = 0.035) and Kansas GWI criteria (p < 0.001) were seen in the three or more mTBI group. Results suggest two mTBIs increase risk of health symptoms, but three mTBIs may be the threshold needed to sustain chronic symptom reporting needed for a formal diagnosis. These findings highlight the importance of implementing policies and procedures monitoring head injuries in military personnel.

Repeated low-dose organophosphate DFP exposure leads to the development of depression and cognitive impairment in a rat model of Gulf War Illness

Approximately 175,000-250,000 of the returning veterans from the 1991 Persian Gulf War exhibit chronic multi-symptom illnesses that includes neurologic co-morbidities such as depression, anxiety and cognitive impairments. Amongst a host of causative factors, exposure to low levels of the nerve agent Sarin has been strongly implicated for expression of Gulf War Illness (GWI). Nerve agents similar to pesticides are organophosphate (OP) compounds. There is evidence from civilian population that exposure to OPs such as in agricultural workers and nerve agents such as the survivors and first-responders of the Tokyo subway Sarin gas attack suffer from chronic neurological problems similar to GWI symptoms. Given this unique chemical profile, OPs are ideal to study the effects of nerve agents and develop models of GWI in civilian laboratories. In this study, we used repeated low-dose exposure to OP agent diisopropyl fluorophosphate (DFP) over a 5-day period to approximate the duration and level of Sarin exposure during the Persian Gulf War. We tested the rats at 3-months post DFP exposure. Using a battery of behavioral assays, we observed the presence of symptoms of chronic depression, anxiety and memory problems as characterized by increased immobility time in the Forced Swim Test, anhedonia in the Sucrose Preference Test, anxiety in the Elevated Plus Maze, and spatial memory impairments in the Object Location Test, respectively. Chronic low dose DFP exposure was also associated with hippocampal neuronal damage as characterized by the presence of Fluoro-Jade staining. Given that OP exposure is considered a leading cause of GWI related morbidities, this animal model will be ideally suited to study underlying molecular mechanisms for the expression of GWI neurological symptoms and identify drugs for the effective treatment of GWIs.

Determinants of chronic physical health conditions in Canadian Veterans

Introduction: Limited information is available about the determinants of chronic health conditions of Veterans despite the increasingly perilous nature of military engagements in recent decades. Methods: Econometric analysis, using probit and negative binomial models, was conducted on the basis of data from a cross-sectional self-reported health survey of Canadian Veterans to investigate the determinants of musculoskeletal, respiratory, gastrointestinal, and cardiovascular health conditions; pain; and diabetes. Results: The results stress the role of military service–related factors in the increased likelihood of chronic physical health conditions in Canadian Veterans. Army Veterans had an increased probability of musculoskeletal (0.08, p ≤ 0.001) and gastrointestinal (0.05, p ≤ 0.001) conditions and pain (0.07, p ≤ 0.01). Veterans who were deployed had an increased risk of musculoskeletal conditions (0.08, p ≤ 0.001) and pain (0.06, p ≤ 0.001). In terms of non–service-related factors, the results confirm the role of obesity as a statistically significant determinant of chronic musculoskeletal, respiratory, and cardiovascular conditions; pain; and diabetes. Female Veterans were also at higher risk of respiratory and gastrointestinal conditions. Low-income Veterans have increased probability of musculoskeletal, gastrointestinal, pain, and cardiovascular conditions, and the risk decreased with rising income level. Finally, Veterans with mental health conditions had increased odds of musculoskeletal (OR = 2.79, p ≤ 0.001), respiratory (OR = 2.40, p ≤ 0.001), gastrointestinal (3.66, p ≤ 0.001), pain (OR = 2.61, p ≤ 0.001), and cardiovascular (OR = 1.45, p ≤ 0.01) conditions and diabetes (OR = 1.37, p ≤ 0.05). Discussion: The findings have important clinical and health resource use implications as Veterans seek treatment in community settings once they transition from military to civilian life. They also serve to advance the research agenda on the health of Veterans, an understudied population in Canada.

Recent research on Gulf War illness and other health problems in veterans of the 1991 Gulf War: Effects of toxicant exposures during deployment

Veterans of Operation Desert Storm/Desert Shield - the 1991 Gulf War (GW) - are a unique population who returned from theater with multiple health complaints and disorders. Studies in the U.S. and elsewhere have consistently concluded that approximately 25-32% of this population suffers from a disorder characterized by symptoms that vary somewhat among individuals and include fatigue, headaches, cognitive dysfunction, musculoskeletal pain, and respiratory, gastrointestinal and dermatologic complaints. Gulf War illness (GWI) is the term used to describe this disorder. In addition, brain cancer occurs at increased rates in subgroups of GW veterans, as do neuropsychological and brain imaging abnormalities. Chemical exposures have become the focus of etiologic GWI research because nervous system symptoms are prominent and many neurotoxicants were present in theater, including organophosphates (OPs), carbamates, and other pesticides; sarin/cyclosarin nerve agents, and pyridostigmine bromide (PB) medications used as prophylaxis against chemical warfare attacks. Psychiatric etiologies have been ruled out. This paper reviews the recent literature on the health of 1991 GW veterans, focusing particularly on the central nervous system and on effects of toxicant exposures. In addition, it emphasizes research published since 2008, following on an exhaustive review that was published in that year that summarizes the prior literature (RACGWI, 2008). We conclude that exposure to pesticides and/or to PB are causally associated with GWI and the neurological dysfunction in GW veterans. Exposure to sarin and cyclosarin and to oil well fire emissions are also associated with neurologically based health effects, though their contribution to development of the disorder known as GWI is less clear. Gene-environment interactions are likely to have contributed to development of GWI in deployed veterans. The health consequences of chemical exposures in the GW and other conflicts have been called "toxic wounds" by veterans. This type of injury requires further study and concentrated treatment research efforts that may also benefit other occupational groups with similar exposure-related illnesses.