Physical and Mental Health Status of Gulf War and Gulf Era Veterans: Results From a Large Population-Based Epidemiological Study

Irritable Bowel Syndrome in Veterans With Gulf War Illness Evaluated at VA's War-Related Illness and Injury Study Center

INTRODUCTION

Excess rates of Gulf War illness (GWI) and irritable bowel syndrome (IBS), two chronic multisymptom illnesses, have long been documented among nearly 700,000 veterans who served in the 1990-1991 Persian Gulf War. We sought to report the prevalence, characteristics, and association of GWI and IBS decades after the war in a clinical cohort of deployed Gulf War veterans (GWVs) who were evaluated at the Department of Veterans Affairs' War Related Illness and Injury Study Center (WRIISC) for unexplained chronic symptoms.

MATERIALS AND METHODS

We analyzed data gathered from clinical intake questionnaires of deployed GWVs who were evaluated at WRIISC clinics between 2008 and 2020. We applied Centers for Disease Control (CDC) criteria to determine the prevalence of severe GWI. IBS was identified using Rome IV diagnostic criteria (current IBS) and veterans' self-reported "history of physician-diagnosed IBS." We examined associations between IBS and GWI using bivariate analyses and multivariable logistic regression.

RESULTS

Among the N = 578 GWVs evaluated by the WRIISC, severe GWI (71.8%), history of physician-diagnosed IBS (50.3%) and current IBS (42.2%) were all highly prevalent. Nearly half of GWVs with severe GWI met Rome criteria for IBS (45.8%), and over half reported a history of physician-diagnosed IBS (56.1%). In multivariable models, severe GWI was significantly associated both with current IBS (adjusted odds ratio (aOR): 1.68, 95% CI: 1.11, 2.54) and with veteran-reported history of physician-diagnosed IBS (aOR: 2.15, 95% CI: 1.43, 2.23). IBS with diarrhea (IBS-D) was the most common subtype among GWVs with current IBS (61.1%). However, IBS-mixed affected a significantly greater proportion of veterans with severe GWI, compared to veterans who did not have severe GWI (P = .03).

CONCLUSIONS

More than 20 years after the Persian Gulf War, our findings indicate a high degree of comorbidity between severe GWI and IBS among deployed GWVs seeking care for unexplained illnesses. Our results suggest GWVs with GWI should be screened for IBS for which evidence-based treatments are available and could potentially reduce symptom burden. Conversely, symptoms of IBS should trigger additional evaluation for non-gastrointestinal symptoms in deployed Gulf War veterans to identify possible GWI and ensure a comprehensive approach to care.

Biomarkers Associated with Depression Improvement in Veterans with Gulf War Illness Using the Low-Glutamate Diet

Gulf War Illness (GWI) is a chronic multi-symptom neurological disorder affecting veterans of the Gulf War that is commonly comorbid with depression. A secondary data analysis was conducted to examine serum homocysteine and inflammatory cytokines (IFN-γ, IL-6, IL-1β, TNF-α) as potential biomarkers of depression improvement among veterans with GWI after a one-month dietary intervention aimed at reducing excitotoxicity and increasing micronutrients. Analyses, including multiple linear and logistic regression, were conducted in R studio. Dietary adherence was estimated using a specialized excitotoxin food frequency questionnaire (FFQ), and depression was measured using the Center for Epidemiologic Studies Depression (CES-D) scale. After one month on the diet, 52% of participants reported a significant decrease in depression (p < 0.01). Greater dietary adherence (FFQ) was associated with increased likelihood of depression improvement; OR (95% CI) = 1.06 (1.01, 1.11), (p = 0.02). Reduced homocysteine was associated with depression improvement after adjusting for FFQ change (β = 2.58, p = 0.04), and serum folate and vitamin B12 were not mediators of this association. Reduction in IFN-γ was marginally associated with likelihood of depression improvement (OR (95% CI) = 1.11 (0.00, 1.42), (p = 0.06)), after adjustment for potential confounders. Findings suggest that homocysteine, and possibly IFN-γ, may serve as biomarkers for depression improvement in GWI. Larger trials are needed to replicate this work.

Crisis in the gut: navigating gastrointestinal challenges in Gulf War Illness with bioengineering

Gulf War Illness (GWI) is characterized by a wide range of symptoms that manifests largely as gastrointestinal symptoms. Among these gastrointestinal symptoms, motility disorders are highly prevalent, presenting as chronic constipation, stomach pain, indigestion, diarrhea, and other conditions that severely impact the quality of life of GWI veterans. However, despite a high prevalence of gastrointestinal impairments among these veterans, most research attention has focused on neurological disturbances. This perspective provides a comprehensive overview of current in vivo research advancements elucidating the underlying mechanisms contributing to gastrointestinal disorders in GWI. Generally, these in vivo and in vitro models propose that neuroinflammation alters gut motility and drives the gastrointestinal symptoms reported in GWI. Additionally, this perspective highlights the potential and challenges of in vitro bioengineering models, which could be a crucial contributor to understanding and treating the pathology of gastrointestinal related-GWI.

Comparison of Health Outcomes Over Time Among Women 1990-1991 Gulf War Veterans, Women 1990-1991 Gulf Era Veterans, and Women in the U.S. General Population

INTRODUCTION

The aim of this study is to examine health over almost 20 years of follow-up among women Gulf War veterans and women Gulf Era veterans and compare their health to that of women in the U.S. general population.

METHODS

We used data from a health survey of 1,274 women Gulf War veteran and Gulf Era veteran participants of the Gulf War Longitudinal Study who responded to all three waves. Data on the U.S. population of women came from the 1999-2000, 2005-2006, and 2011-2014 National Health and Nutrition Examination Survey (NHANES). Generalized estimating equations (GEEs) were used to compare the report of disease over time in women Gulf War and Gulf Era veterans. Differences in prevalence at the three survey timepoints were calculated between women Gulf War veterans and the NHANES women population, and women Gulf War Era veterans and the NHANES women population.

RESULTS

Women veterans who deployed to the 1990-1991 Gulf War report poorer health than women veterans who served during the same time but did not deploy. Women veterans reported a lower prevalence of hypertension, stroke, and diabetes than women in the NHANES sample. Women veterans also reported a higher prevalence of arthritis, chronic obstructive pulmonary disease, and skin cancer than women in the NHANES sample.

CONCLUSIONS

This study is the first to characterize the health of a population-based cohort of women Gulf War and women Gulf Era veterans over time and compare it with women's health in a civilian NHANES population. This demonstrates the value of epidemiological research on women veterans and the importance of developing longitudinal cohorts across genders.

Military Environmental Exposures

ABSTRACT

The passage of the PACT Act of 2022 expanded the services veterans receive through the U.S. Department of Veterans Affairs (VA), ensuring they now qualify for benefits if they've been exposed to certain toxins during their military service. This significant expansion of VA benefits also highlights the need for nurses and other health providers working outside the VA system-who care for millions of veterans-to be well-informed about their patients' military experiences and any potential environmental exposures and health impacts. In this article, the author raises awareness of military environmental exposures and offers guidance about exposure-informed care.

Association of Atherosclerotic Cardiovascular Disease, Hypertension, Diabetes, and Hyperlipidemia With Gulf War Illness Among Gulf War Veterans

BACKGROUND

Approximately 30% of the 700 000 Gulf War veterans report a chronic symptom-based illness of varying severity referred to as Gulf War illness (GWI). Toxic deployment-related exposures have been implicated in the cause of GWI, some of which contribute to metabolic dysregulation and lipid abnormalities. As this cohort ages, the relationship between GWI and atherosclerotic cardiovascular disease (ASCVD) is a growing concern. We evaluated associations between GWI and ASCVD, diabetes, hyperlipidemia, and hypertension in veterans of the Gulf War (1990-1991).

METHODS AND RESULTS

Analysis of survey data collected in 2014 to 2016 from a national sample of deployed Gulf War veterans (n=942) and Veterans Health Administration electronic health record data (n=669). Multivariable logistic regression models tested for associations of GWI with self-reported ASCVD, diabetes, hyperlipidemia, and hypertension, controlling for confounding factors. Separate models tested for GWI associations with ASCVD and risk factors documented in the electronic health record. GWI was associated with self-reported hypertension (adjusted odds ratio [aOR], 1.67 [95% CI, 1.18-2.36]), hyperlipidemia (aOR, 1.46 [95% CI, 1.03-2.05]), and ASCVD (aOR, 2.65 [95% CI, 1.56-4.51]). In the subset of veterans with electronic health record data, GWI was associated with documented diabetes (aOR, 2.34 [95% CI, 1.43-3.82]) and hypertension (aOR, 2.84 [95% CI, 1.92-4.20]). Hyperlipidemia and hypertension served as partial mediators of the association between GWI and self-reported ASCVD.

CONCLUSIONS

Gulf War veterans with GWI had higher odds of hyperlipidemia, hypertension, diabetes, and ASCVD compared with Gulf War veterans without GWI. Further examination of the mechanisms underlying this association, including a possible shared exposure-related mechanism, is necessary.

Delayed cognitive impairments in a rat model of Gulf War Illness are stimulus-dependent

Gulf War Illness (GWI) collectively describes the multitude of central and peripheral disturbances affecting soldiers who served in the 1990-1991 Gulf War. While the mechanisms responsible for GWI remain elusive, the prophylactic use of the reversible acetylcholinesterase inhibitor, pyridostigmine bromide (PB), and war-related stress have been identified as chief factors in GWI pathology. Post-deployment stress is a common challenge faced by veterans, and aberrant cholinergic and/or immune responses to these psychological stressors may play an important role in GWI pathology, especially the cognitive impairments experienced by many GWI patients. Therefore, the current study investigated if an immobilization stress challenge would produce abnormal responses in PB-treated rats three months later. Results indicate that hippocampal cholinergic responses to an immobilization stress challenge are impaired three months after PB administration. We also assessed if an immune or stress challenge reveals deficits in PB-treated animals during hippocampal-dependent learning and memory tasks at this delayed timepoint. Novel object recognition (NOR) testing paired with either acute saline or lipopolysaccharide (LPS, 30 µg/kg, i.p.), as well as Morris water maze (MWM) testing was conducted approximately three months after PB administration and/or repeated restraint stress. Rats with a history of PB treatment exhibited 24-hour hippocampal-dependent memory deficits when challenged with LPS, but not saline, in the NOR task. Similarly, in the same cohort, PB-treated rats showed 24-hour memory deficits in the MWM task. Ultimately, these studies highlight the long-term effects of PB treatment on hippocampal function and provide insight into the progressive cognitive deficits observed in veterans with GWI.

Self-reported gastrointestinal disorders among veterans with gulf war illness with and without posttraumatic stress disorder

BACKGROUND

Gulf War Illness (GWI) is a chronic, multi-symptom disorder affecting 25%-32% of Gulf War veterans. Veterans with GWI disproportionately suffer from gastrointestinal (GI) disorders. Given the increasing evidence supporting a gut-brain axis, we explore the relationship between post-traumatic stress disorder (PTSD), GWI, and self-reported GI disorders among GW veterans.

METHODS

Veterans from the Gulf War Era Cohort and Biorepository responded to a mail-based survey (N = 1058). They were stratified by GWI (Centers for Disease Control definition) and PTSD status. This yielded three groups: GWI-, GWI+/PTSD-, and GWI+/PTSD+. Multivariable logistic regression adjusting for demographic and military characteristics examined associations between GWI/PTSD groups and GI disorders. Results were expressed as adjusted odds ratios (aOR) with 95% confidence intervals (95% CI).

KEY RESULTS

The most frequently reported GI disorders were irritable bowel syndrome (IBS), gastroesophageal reflux disease (GERD), and colon polyps (CP). The GWI+/PTSD+ group had a higher odds of these disorders than the GWI+/PTSD- group (aOR_IBS  = 3.12, 95% CI: 1.93-5.05; aOR_GERD  = 2.04, 95% CI: 1.44-2.90; aOR_CP  = 1.85, 95% CI: 1.23-2.80), which had a higher odds of these disorders than the GWI- group (aOR_IBS  = 4.38, 95% CI: 1.55-12.36; aOR_GERD  = 2.51 95% CI: 1.63-3.87; aOR_CP  = 2.57, 95% CI: 1.53-4.32).

CONCLUSIONS & INFERENCES

GW veterans with GWI and PTSD have significantly higher odds of specific self-reported GI disorders than the other groups. Given the known bidirectional influences of the gut and brain, these veterans may benefit from a holistic healthcare approach that considers biopsychosocial contributors to the assessment and management of disease.

Spatial Analysis of Access to Psychiatrists for US Military Personnel and Their Families

IMPORTANCE

Military service members and their families have greater mental health care needs compared with their civilian counterparts. Some communities have inadequate access to psychiatrists for this population.

OBJECTIVES

To identify geographic variations in the availability of military and civilian psychiatrists within a 30-minute driving time of TRICARE (the US military's health care program) beneficiaries' communities and compare the likelihood of living in areas with inadequate access to psychiatrists for historically underserved and other communities.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study of all zip code communities in the continental US, Hawaii, and Alaska with at least one TRICARE beneficiary between January 1, 2016, and September 30, 2020, combines data from the Defense Health Agency, the National Plan and Provider Enumeration System, and the US Census to estimate a logistic regression to compare differences between communities with and without a psychiatrist shortage. Data were analyzed from September 2021 to November 2022.

MAIN OUTCOMES AND MEASURES

A community's likelihood of having a shortage of military and civilian psychiatrists within a 30-minute driving time and a community's likelihood of having no psychiatrists. Odds ratios were calculated to estimate likelihood of the outcomes.

RESULTS

This study includes 39 487 unique communities where 13% of the population is Black and 14% of the population is Hispanic. During the study period, 35% of TRICARE beneficiaries lived in communities with a shortage of both military and civilian psychiatrists, and 6% lived in communities with no access to military or civilian psychiatrists. Low-income communities with high income inequality were 1.64 (95% CI, 1.30-2.07) times more likely to have inadequate access to psychiatrists and 2.59 (95% CI, 1.82-3.69) times more likely to have no access to psychiatrists, compared with reference communities (average income without high income inequality); low-income communities without high income inequality were 1.37 (95% CI, 1.05-1.78) times more likely to have inadequate access to psychiatrists and 1.93 (95% CI, 1.28-2.89) times more likely to have no access to psychiatrists. Rural communities were 6.65 (95% CI, 5.09-8.69) times more likely to have inadequate access to psychiatrists than urban communities.

CONCLUSIONS AND RELEVANCE

In this cohort study of US communities, 35% of TRICARE beneficiaries lived in communities with inadequate access to psychiatrists. Psychiatric capacity was structurally inequitable along 2 separate dimensions: the income gradient and rurality. Developing targeted strategies for these shortage areas could alleviate disparities.

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.

Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Clinical Normative Data for Gulf War Veterans

OBJECTIVE

Heterogenous test batteries and methods applied in neurocognitive research on Gulf War Veterans (GWVs) limit the translation of findings to clinical practice. A clinical data set is necessary.

METHODS

Neurocognitive screening data from treatment-seeking GWVs were collected from multiple sites and compiled, informed by consideration of performance validity.

RESULTS

Repeatable Battery for the Assessment of Neuropsychological Status scores revealed the cognitive profile for GWVs (n = 189) as poorer across multiple domains when compared with similarly educated, nonveteran peers. However, mean scores generally remained within normal clinical limits. Data tables are presented to establish a comparison group for use in clinical care.

CONCLUSIONS

When assessing cognitive symptoms in GWVs, attention to education level and interpretation of subtle deficits is warranted. Current results highlight the importance of nuanced translation of neurocognitive research findings into clinical practice with GWVs.

Complementary/integrative healthcare utilization in US Gulf-War era veterans: Descriptive analyses based on deployment history, combat exposure, and Gulf War Illness

Complementary and integrative health (CIH) approaches have gained empirical support and are increasingly being utilized among veterans to treat a myriad of conditions. A cluster of medically unexplained chronic symptoms including fatigue, headaches, joint pain, indigestion, insomnia, dizziness, respiratory disorders, and memory problems, often referred to as Gulf War Illness (GWI) prominently affect US Gulf War era (GWE) veterans, yet little is known about CIH use within this population. Using data collected as part of a larger study (n = 1153), we examined the influence of demographic characteristics, military experiences, and symptom severity on CIH utilization, and utilization differences between GWE veterans with and without GWI. Over half of the sample (58.5%) used at least one CIH modality in the past six months. Women veterans, white veterans, and veterans with higher levels of education were more likely to use CIH. GWE veterans with a GWI diagnosis and higher GWI symptom severity were more likely to use at least one CIH treatment in the past six months. Over three quarters (82.7%) of veterans who endorsed using CIH to treat GWI symptoms reported that it was helpful for their symptoms. Almost three quarters (71.5%) of veterans indicated that they would use at least one CIH approach if it was available at VA. Results provide a deeper understanding of the likelihood and characteristics of veterans utilizing CIH to treat health and GWI symptoms and may inform expansion of CIH modalities for GWE veterans, particularly those with GWI.

Impact of gulf war toxic exposures after mild traumatic brain injury

Chemical and pharmaceutical exposures have been associated with the development of Gulf War Illness (GWI), but how these factors interact with the pathophysiology of traumatic brain injury (TBI) remains an area of study that has received little attention thus far. We studied the effects of pyridostigmine bromide (an anti-nerve agent) and permethrin (a pesticide) exposure in a mouse model of repetitive mild TBI (r-mTBI), with 5 impacts over a 9-day period, followed by Gulf War (GW) toxicant exposure for 10 days beginning 30 days after the last head injury. We then assessed the chronic behavioral and pathological sequelae 5 months after GW agent exposure. We observed that r-mTBI and GWI cumulatively affect the spatial memory of mice in the Barnes maze and result in a shift of search strategies employed by r-mTBI/GW exposed mice. GW exposure also produced anxiety-like behavior in sham animals, but r-mTBI produced disinhibition in both the vehicle and GW treated mice. Pathologically, GW exposure worsened r-mTBI dependent axonal degeneration and neuroinflammation, increased oligodendrocyte cell counts, and increased r-mTBI dependent phosphorylated tau, which was found to colocalize with oligodendrocytes in the corpus callosum. These results suggest that GW exposures may worsen TBI-related deficits. Veterans with a history of both GW chemical exposures as well as TBI may be at higher risk for worse symptoms and outcomes. Subsequent exposure to various toxic substances can influence the chronic nature of mTBI and should be considered as an etiological factor influencing mTBI recovery.

Cannabis use and suicide risk among Gulf War veterans

Cannabis use has been indicated as a risk factor for suicide in veterans. This study of Gulf War veterans tested the relationship between self-report past year cannabis use and (a) past year suicidal ideation and (b) risk for suicidal behavior. Data were from a national sample (N = 1126) of Gulf War veterans. Logistic regression models indicated cannabis use was associated with past year suicidal ideation and elevated risk for suicidal behavior, independent of key covariates. In corroboration with research on other military populations, this study indicates a potentially concerning association between cannabis use and suicide risk in Gulf War veterans.

Preliminary Findings from the Gulf War Women’s Cohort: Reproductive and Children’s Health Outcomes among Women Veterans

Reproductive outcomes, such as preterm birth, miscarriage/stillbirth, and pre-eclampsia, are understudied in veterans, particularly among Gulf War veterans (GWVs). During deployment, women GWVs were exposed to toxicant and nontoxicant exposures that may be associated with adverse reproductive and developmental outcomes. The data come from a survey of 239 participants from northeastern and southern U.S. cohorts of women veterans. The questionnaire collected information about the service history, current and past general health, reproductive and family health, demographic information, and deployment exposures. Odds ratios were computed with 95% confidence intervals between exposures in theater and reproductive/children’s health outcomes. GWVs experienced adverse reproductive outcomes: 25% had difficulty conceiving, and 31% had a pregnancy that ended in a miscarriage or stillbirth. Pregnancy complications were common among GWVs: 23% had a high-risk pregnancy, and 16% were diagnosed with pre-eclampsia. About a third of GWVs reported their children (38%) had a developmental disorder. Use of pesticide cream during deployment was associated with higher odds of all reproductive and developmental outcomes. The results demonstrate that GWVs experienced reproductive and children’s health outcomes at potentially high rates, and exploratory analyses suggest pesticide exposure as associated with higher odds of adverse reproductive outcomes. Future longitudinal studies of women veterans should prioritize examining reproductive and children’s health outcomes.

Pyridostigmine bromide elicits progressive and chronic impairments in the cholinergic anti-inflammatory pathway in the prefrontal cortex and hippocampus of male rats

Gulf War Illness (GWI) is a multi-symptom illness that continues to affect over 250,000 American Gulf War veterans. The causes of GWI remain equivocal; however, prophylactic use of the acetylcholinesterase inhibitor pyridostigmine bromide (PB), and the stress of combat have been identified as two potential causative factors. Both PB and stress alter acetylcholine (ACh), which mediates both cognition and anti-inflammatory responses. As inflammation has been proposed to contribute to the cognitive deficits and immune dysregulation in GWI, the goal of this study was to determine the long-term effects of PB and stress on the cholinergic anti-inflammatory pathway in the central nervous system and periphery. We used our previously established rat model of GWI and in vivo microdialysis to assess cholinergic neurochemistry in the prefrontal cortex (PFC) and hippocampus following a mild immune challenge (lipopolysaccharide; LPS). We then examined LPS-induced changes in inflammatory markers in PFC and hippocampal homogenates. We found that PB treatment produces a long-lasting potentiation of the cholinergic response to LPS in both the PFC and hippocampus. Interestingly, this prolonged effect of PB treatment enhancing cholinergic responses to LPS was accompanied by paradoxical increases in the release of pro-inflammatory cytokines in these brain regions. Collectively, these findings provide evidence that neuroinflammation resulting from dysregulation of the cholinergic anti-inflammatory pathway is a mechanistic mediator in the progression of the neurochemical and neurocognitive deficits in GWI and more broadly suggest that dysregulation of this pathway may contribute to neuroinflammatory processes in stress-related neurological disorders.

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Inflammation is thought to contribute to the progressive nature of GWI pathology.

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PB potentiates the central cholinergic response to LPS over time in model of GWI.

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PB progressively exacerbates the neuroinflammatory response to LPS.

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GWI may result from the dysregulation of the cholinergic anti-inflammatory pathway.

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.

The impact of post-traumatic stress on quality of life and fatigue in women with Gulf War Illness

Background

Gulf War Illness (GWI) is a chronic, multi-symptomatic disorder characterized by fatigue, muscle pain, cognitive problems, insomnia, rashes, and gastrointestinal issues affecting an estimated 30% of the ~ 750,000 returning military Veterans of the 1990–1991 Persian Gulf War. Female Veterans deployed to combat in this war report medical symptoms, like cognition and respiratory troubles, at twice the rate compared to non-deployed female Veterans of the same era. The heterogeneity of GWI symptom presentation complicates diagnosis as well as the identification of effective treatments. This is exacerbated by the presence of co-morbidities. Defining subgroups of the illness may help alleviate these complications. One clear grouping is along the lines of gender. Our aim is to determine if women with GWI can be further subdivided into distinct subgroups based on post-traumatic stress disorder (PTSD) symptom presentation.

Methods

Veterans diagnosed with GWI (n = 35) and healthy sedentary controls (n = 35) were recruited through the Miami Veterans Affairs Medical Health Center. Symptoms were assessed via the RAND short form health survey, the multidimensional fatigue inventory, and the Davidson trauma scale. Hierarchal regression modeling was performed on measures of health and fatigue with PTSD symptoms as a covariate. This was followed by univariate analyses conducted with two separate GWI groups based on a cut-point of 70 for their total Davidson trauma scale value and performing heteroscedastic t-tests across all measures.

Results

Based on the distinct differences found in PTSD symptomology regarding all health and trauma symptoms, two subgroups were derived within female GWI Veterans. Hierarchical regression models displayed the comorbid effects of GWI and PTSD, as both conditions had measurable impacts on quality of life and fatigue (ΔR² = 0.08–0.672), with notable differences in mental and emotional measures. Overall, a cut point analysis indicated poorer quality of life and greater fatigue within all measures for women with GWI and PTSD symptoms in comparison to those women with GWI without PTSD symptoms and healthy controls.

Conclusions

Our current findings support the understanding that comorbid symptoms of GWI and PTSD subsequently result in poorer quality of life and fatigue, along with establishing the possibility of varying clinical presentations.

Posttraumatic Stress Disorder Does Not Compromise Behavioral Pain Treatment: Secondary Analysis of a Randomized Clinical Trial Among Veterans

BACKGROUND

Individuals with posttraumatic stress disorder (PTSD) and chronic pain evince different presentations, coping strategies, and treatment utilization patterns than individuals with chronic pain alone. Theorists have suggested that comorbid PTSD may complicate chronic pain treatment, and that integrated pain and PTSD treatment may be preferable to pain treatment alone.

OBJECTIVE

Assess whether comorbid PTSD moderates Veterans' response to yoga and/or cognitive behavioral therapy (CBT) for pain.

METHODS

Veterans with Gulf War illness (n = 75) were assessed using the Brief Pain Inventory at baseline and posttreatment as part of a randomized clinical trial. PTSD status was abstracted from participants' medical records.

RESULTS

PTSD+ participants (n = 41) reported more pain at baseline than PTSD- participants (n = 34; d = .66, p < .01). PTSD+ participants experienced more improvement in pain from baseline to posttreatment than PTSD- participants by a small to moderate, marginally statistically significant amount (d = .39, p = .07). The relationship between PTSD and treatment outcome was not moderated by treatment type (yoga vs CBT; p = .99). Observation of treatment responses across PTSD status (+ vs -) and treatment (yoga vs CBT) revealed that PTSD+ participants responded well to yoga.

CONCLUSION

PTSD is not associated with reduced effectiveness of behavioral chronic pain treatment among Veterans with Gulf War illness. Therefore behavioral pain treatment should be made readily available to Veterans with pain and PTSD. Yoga deserves further consideration as a treatment for pain among individuals with PTSD.

The Effect of the Low Glutamate Diet on the Reduction of Psychiatric Symptoms in Veterans With Gulf War Illness: A Pilot Randomized-Controlled Trial

The objective of this pilot study was to examine the effects of the low glutamate diet on anxiety, post-traumatic stress disorder (PTSD), and depression in veterans with Gulf War Illness (GWI). The low glutamate diet removes dietary excitotoxins and increases consumption of micronutrients which are protective against glutamatergic excitotoxicity. This study was registered at ClinicalTrials.gov (NCT#03342482). Forty veterans with GWI completed psychiatric questionnaires at baseline and after 1-month following the low glutamate diet. Participants were then randomized into a double-blind, placebo-controlled crossover challenge with monosodium glutamate (MSG; a dietary excitotoxin) vs. placebo over three consecutive days per week, with assessments on day three. Data were analyzed across the full sample and with participants categorized by baseline symptom severity. Pre-post-dietary intervention change scores were analyzed with Wilcoxon signed-rank tests and paired sample t-tests across the full sample, and changes across symptom severity categories were analyzed using ANOVA. Crossover challenge results were analyzed with linear mixed modeling accounting for challenge material (MSG v. placebo), sequence (MSG/placebo v. placebo/MSG), period (challenge week 1 v. week 2), pre-diet baseline symptom severity category (minimal/mild, moderate, or severe), and the challenge material^*symptom severity category interaction. A random effect of ID (sequence) was also included. All three measures showed significant improvement after 1 month on the diet, with significant differences between baseline severity categories. Individuals with severe psychological symptoms at baseline showed the most improvement after 1 month on the diet, while those with minimal/mild symptoms showed little to no change. Modeling results from the challenge period demonstrated a significant worsening of anxiety from MSG in only the most severe group, with no significant effects of MSG challenge on depression nor PTSD symptoms. These results suggest that the low glutamate diet may be an effective treatment for depression, anxiety, and PTSD, but that either (a) glutamate is only a direct cause of symptoms in anxiety, or (b) underlying nutrient intake may prevent negative psychiatric effects from glutamate exposure. Future, larger scale clinical trials are needed to confirm these findings and to further explore the potential influence of increased micronutrient intake on the improvements observed across anxiety, PTSD, and depression.

Gulf War Era Veterans' perspectives on research: a qualitative study

AIMS

Many veterans of the 1990-1991 Gulf War Era (GWE) have experienced poorly understood health issues. In response to challenges recruiting this population for research, we conducted focus groups and semi-structured phone interviews with GWE veterans and subject matter experts (SMEs) to explore GWE veterans' perceptions about research.

MAIN METHODS

Transcribed discussions were content-analyzed. Participants discussed research-related motivators and barriers identified among other populations, and nuances that may be specific to GWE veterans.

KEY FINDINGS

Examples of motivating factors included: seeking answers about causes of and treatment for health issues; helping oneself; and helping other veterans. Examples of barriers included: distrust and dissatisfaction with federal entities; lack of research follow-through; and concerns about privacy and confidentiality.

SIGNIFICANCE

Researchers can use this information to better address GWE veterans' concerns and motivate them to participate in research. Inclusion of GWE veterans in research will allow researchers and clinicians to better understand and address health issues affecting this population.

The Health of Gulf War and Gulf Era Veterans Over Time: U.S. Department of Veterans Affairs' Gulf War Longitudinal Study

OBJECTIVE

The aim of this study was to describe the self-reported physical and mental health over the course over 19 years of follow up of a population-based cohort of Gulf War and Gulf Era veterans.

METHODS

A multi-modal health survey of 6338 Gulf War and Gulf Era veterans who participated in all three waves of the longitudinal study.

RESULTS

Gulf War and Gulf War Era veterans experienced an increase in prevalence of chronic disease over time. The adjusted odds ratios suggest that Gulf War veterans not only had significantly higher odds of reporting medical conditions, but also began to report them earlier.

CONCLUSIONS

The findings from this analysis suggest that Gulf War veterans are not only more likely than their non-deployed counterparts to report chronic disease, they were more likely to report it earlier.

Experimental respiratory exposure to putative Gulf War toxins promotes persistent alveolar macrophage recruitment and pulmonary inflammation

AIMS

Respiratory disorders are a prominent component of Gulf War Illness. Although much of the underlying mechanisms of Gulf War Illness remain undefined, chronic immune dysfunction is a consistent feature of this multi-symptomatic, multi-organ disorder. Alveolar macrophages represent the predominant mononuclear phagocytes of the pulmonary mucosa, orchestrating the host response to pathogens and environmental stimuli. Herein, we sought to characterize the innate immune response of the pulmonary mucosa, with a focus on macrophages, to experimental respiratory exposure to two putative Gulf War Toxins (GWTs).

MATERIALS AND METHODS

Utilizing commercially available instrumentation, we evaluated the effect of aerosolized exposure to the pesticide malathion and diesel exhaust particulate (DEP) on the immune composition and inflammatory response of the lung in FVB/N mice using multiparametric spectral cytometry, cytokine analysis, and histology.

KEY FINDINGS

Aerosolized GWTs induced gross pulmonary pathology with transient recruitment of neutrophils and sustained accumulation of alveolar macrophages to the lung for up to two weeks after exposure cessation. High-dimensional cytometry and unbiased computational analysis identified novel myeloid subsets recruited to the lung post-exposure driven by an influx of peripheral monocyte-derived progenitors. DEP and malathion, either alone or in combination, induced soluble mediators in bronchoalveolar lavage indicative of oxidative stress (PGF2α), inflammation (LTB4, TNFα, IL-12), and immunosuppression (IL-10), that were sustained or increased two weeks after exposures concluded.

SIGNIFICANCE

These findings indicate that macrophage accumulation and pulmonary inflammation induced by GWTs continue in the absence of toxin exposure and may contribute to the immunopathology of respiratory Gulf War Illness.

Gastrointestinal problems, mechanisms and possible therapeutic directions in Gulf war illness: a mini review

By its nature, Gulf war illness (GWI) is multisymptomatic and affects several organ systems in the body. Along with other symptoms, veterans who suffer from GWI commonly report chronic gastrointestinal issues such as constipation, pain, indigestion, etc. However, until recently, most attention has been focused on neurological disturbances such as cognitive impairments, chronic fatigue, and chronic pain among affected veterans. With such high prevalence of gastrointestinal problems among Gulf war (GW) veterans, it is surprising that there is little research to investigate the mechanisms behind these issues. This review summarizes all the available works on the mechanisms behind gastrointestinal problems in GWI that have been published to date in various databases. Generally, these studies, which were done in rodent models, in vitro and human cohorts propose that an altered microbiome, a reactive enteric nervous system or a leaky gut among other possible mechanisms are the major drivers of gastrointestinal problems reported in GWI. This review aims to draw attention to the gastrointestinal tract as an important player in GWI disease pathology and a potential therapeutic target.

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.

Post-traumatic stress impact on health outcomes in Gulf War Illness

BACKGROUND

Gulf War Illness (GWI) is a chronic, multi-symptomatic disorder affecting an estimated 25-32% of the returning military veterans of the 1990-1991 Persian Gulf War. GWI presents with a wide range of symptoms including fatigue, muscle pain, cognitive problems, insomnia, rashes and gastrointestinal issues and continues to be a poorly understood illness. This heterogeneity of GWI symptom presentation complicates diagnosis as well as the identification of effective treatments. Defining subgroups of the illness may help alleviate these complications. Our aim is to determine if GWI can be divided into distinct subgroups based on PTSD symptom presentation.

METHODS

Veterans diagnosed with GWI (n = 47) and healthy sedentary veteran controls (n = 52) were recruited through the Miami Affairs (VA) Medical Health Center. Symptoms were assessed via the RAND short form health survey (36), the multidimensional fatigue inventory, and the Davidson trauma scale. Hierarchal regression modeling was performed on measures of health and fatigue with PTSD symptoms as a covariate. This was followed by univariate analyses conducted with two separate GWI groups based on a cut-point of 70 for their total Davidson Trauma Scale value and performing heteroscedastic t-tests across all measures.

RESULTS

Overall analyses returned two symptom-based subgroups differing significantly across all health and trauma symptoms. These subgroups supported PTSD symptomatology as a means to subgroup veterans. Hierarchical models showed that GWI and levels of PTSD symptoms both impact measures of physical, social, and emotional consequences of poor health (ΔR2 = 0.055-0.316). However, GWI appeared to contribute more to fatigue measures. Cut-point analysis retained worse health outcomes across all measures for GWI with PTSD symptoms compared to those without PTSD symptoms, and healthy controls. Significant differences were observed in mental and emotional measures.

CONCLUSIONS

Therefore, this research supports the idea that comorbid GWI and PTSD symptoms lead to worse health outcomes, while demonstrating how GWI and PTSD symptoms may uniquely contribute to clinical presentation.

Ocular manifestations and biomarkers of Gulf War Illness in US veterans

Gulf War Illness (GWI) is a multisystem disease with variable presentations, making diagnosis difficult. Non-invasive biomarkers would aid in disease diagnosis. We hypothesized that the eye could serve as a biomarker for GWI. We performed a retrospective case–control study using a sample of 1246 patients seen during a 5-month period in an optometry clinic. We identified veterans who were active duty during the Gulf War Era and either had a questionnaire-based diagnosis of GWI (cases) or did not (controls). Medical records were reviewed for eye and medical co-morbidities, medication use, and retinal macular and nerve fiber layer (NFL) thicknesses based on optical coherence tomography (OCT) images. Compared to controls (n = 85), individuals with GWI (n = 60) had a higher frequency of dry eye symptoms (50% vs 32.9%, p = 0.039). Multivariable analysis revealed average retinal NFL thickness (odds ratio; OR = 0.95), cup-to-disc ratio (OR = 0.005), age (OR = 0.82), and PTSD (OR = 20.5) were predictors of a GWI diagnosis. We conclude that GWI is associated with dry eye symptoms and RNFL thinning may serve as a biomarker for disease.

Cause-specific mortality risks among U.S. veterans: 25 years after their service in the 1990-1991 gulf war

PURPOSE

There is concern about adverse health effects related to military service in the 1990-1991 Gulf War. This study assessed cause-specific mortality risks among Veterans who served in the war.

METHODS

The mortality of 621,244 veterans deployed to the Gulf War was compared to that of 745,704 Veterans who served during the war but were not deployed to the Gulf Theater. Cause-specific mortality of both deployed and nondeployed was also compared to that of the US general population.

RESULTS

There was no increased risk of disease-specific mortality among deployed Veterans compared to nondeployed. Deployed Veterans did have an increased risk of motor vehicle deaths compared to nondeployed Veterans, (hazard ratio, 1.12, 95% confidence interval, 1.04-1.21). Cause-specific mortality of both deployed and non-deployed Veterans was less than that of the US population. When stratified by gender, only female Veterans, both deployed and nondeployed, had increased risks of suicide compared to the female US population (standardized mortality ratio, 1.40; 95% confidence interval, 1.13-1.71 and standardized mortality ratio, 1.22; 95% confidence interval, 1.05-1.40, respectively).

CONCLUSION

There was no increased risk of disease mortality among Veterans of the 1990-1991 Gulf War. Both deployed and nondeployed female Veterans had increased risks of suicide compared to US female population.

Respiratory illness among Gulf War and Gulf War era veterans who use the Department of Veterans Affairs for healthcare

BACKGROUND

Veterans of the 1990-1991 Gulf War were exposed to a variety of toxic substances during their service that included several airborne hazards, but only a few small studies have assessed respiratory outcomes in Gulf War veterans. This paper presents population prevalence estimates and prevalence ratios of respiratory disease among Gulf War and Gulf War Era veterans who use VA healthcare.

METHODS

A total of 360,909 Gulf War deployed veterans and 323,638 Gulf War Era non-deployed veterans were included in the analysis. Ten-year period prevalence rates (PRs) for fifteen respiratory diseases were calculated for Gulf War and Gulf War Era veterans and period prevalence ratios comparing Gulf War veterans to Gulf War Era veterans were calculated.

RESULTS

The five respiratory conditions with the highest prevalence per 100,000 veterans across both Gulf War deployed and Gulf War Era non-deployed veterans (respectively) were: allergic rhinitis (8,400 and 8,041), chronic obstructive pulmonary disease (4,763 and 4,795), asthma (4,685 and 4,477), chronic airway obstruction (3,983 and 4,059), and chronic sinusitis (2,863 and 2,672). The adjusted PRs showed a small, but significantly increased, elevation in Gulf War-deployed compared to Gulf War Era non-deployed veterans for chronic bronchitis (PR 1.19; 95% CI 1.10, 1.28), emphysema (PR 1.11; 95% CI 1.01, 1.21), chronic airway obstruction (PR 1.09; 95% CI 1.07, 1.12), and chronic obstructive pulmonary disease (PR 1.09; 1.07, 1.11).

DISCUSSION

Gulf War veterans should continue to be monitored in the future to better evaluate the potential long-term consequences on respiratory health.

Longitudinal Assessment of Health Symptoms in Relation to Neurotoxicant Exposures in 1991 Gulf War Veterans: The Ft. Devens Cohort

OBJECTIVE

This analysis examined the relationship between Gulf War (GW) exposures and health symptoms reported in three time periods over 20 years in Ft. Devens Cohort veterans.

METHODS

Repeated logistic regression models examined the association of exposures and health symptoms over time. Models included baseline age, active duty status, post-traumatic stress disorder status, sex, and time since deployment as covariates.

RESULTS

Exposure to tent heaters was associated with increased odds of crying easily and muscle twitching. Exposure to pyridostigmine bromide (PB) pills was associated with increased odds of depression and fatigue. Exposure to the Khamisiyah sarin plume was associated with increased odds of trouble concentrating and crying easily.

CONCLUSION

This longitudinal analysis demonstrated an association between neurotoxicant exposures and increased odds of cognitive/mood, fatigue, and neurological symptoms. In addition, most symptoms increased over time since deployment regardless of exposure.

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.

Improvements in Gulf War Illness Symptoms After Near-Infrared Transcranial and Intranasal Photobiomodulation: Two Case Reports

At least one-fourth of US veterans who served in the 1990-1991 Gulf War (GW) are affected by the chronic symptomatic illness known as Gulf War illness (GWI). This condition typically includes some combination of fatigue, headaches, cognitive dysfunction, musculoskeletal pain, and respiratory, gastrointestinal and dermatologic complaints. To date, effective treatments for GWI have been elusive. Photobiomodulation (PBM) describes the non-pharmacological, non-thermal use of light to stimulate, heal, and protect tissue that has either been injured, is degenerating, or else is at risk of dying. Significant benefits have been reported following application of transcranial PBM to humans with acute stoke, traumatic brain injury (TBI), and dementia. This report describes the first documentation of improved GWI symptoms in two GW veterans following 12 weeks of PBM treatments.

Exercise alters cerebellar and cortical activity related to working memory in phenotypes of Gulf War Illness

Gulf War Illness affects 25–32% of veterans from the 1990–91 Persian Gulf War. Post-exertional malaise with cognitive dysfunction, pain and fatigue following physical and/or mental effort is a defining feature of Gulf War Illness. We modelled post-exertional malaise by assessing changes in functional magnetic resonance imaging at 3T during an N-Back working memory task performed prior to a submaximal bicycle stress test and after an identical stress test 24 h later. Serial trends in postural changes in heart rate between supine and standing defined three subgroups of veterans with Gulf War Illness: Postural Orthostatic Tachycardia Syndrome (GWI-POTS, 15%, n = 11), Stress Test Associated Reversible Tachycardia (GWI-START, 31%, n = 23) and Stress Test Originated Phantom Perception (GWI-STOPP, no postural tachycardia, 54%, n = 46). Before exercise, there were no differences in blood oxygenation level-dependent activity during the N-Back task between control (n = 31), GWI-START, GWI-STOPP and GWI-POTS subgroups. Exercise had no effects on blood oxygenation level-dependent activation in controls. GWI-START had post-exertional deactivation of cerebellar dentate nucleus and vermis regions associated with working memory. GWI-STOPP had significant activation of the anterior supplementary motor area that may be a component of the anterior salience network. There was a trend for deactivation of the vermis in GWI-POTS after exercise. These patterns of cognitive dysfunction were apparent in Gulf War Illness only after the exercise stressor. Mechanisms linking the autonomic dysfunction of Stress Test Associated Reversible Tachycardia and Postural Orthostatic Tachycardia Syndrome to cerebellar activation, and Stress Test Originated Phantom Perception to cortical sensorimotor alterations, remain unclear but may open new opportunities for understanding, diagnosing and treating Gulf War Illness.

Gulf War Illness-associated increases in blood levels of interleukin 6 and C-reactive protein: biomarker evidence of inflammation

OBJECTIVE

Gulf War Illness is a chronic multisymptom disorder severely impacting the health and well-being of many Veterans of the 1990-1991 Gulf War. Symptoms that define the disease include pain, fatigue, mood and memory impairments, gastrointestinal problems, lung disorders, and skin rashes. In our previous biomarker study, we discovered Gulf War Illness-associated proinflammatory blood biomarkers. Therefore, we hypothesized that chronic inflammation causes the symptoms that define this disorder. Testing the chronic inflammation hypothesis is the objective of this study.

RESULTS

The biomarker fingerprint of Gulf War Illness is the end-product of a cascade of proinflammatory cytokine signals. In particular, the observed increase in C-reactive protein predicts a corresponding increase in interleukin 6, the cytokine that stimulates hepatocytes to produce C-reactive protein. Therefore, in this study we measured potential upstream cytokine signals in plasma samples from Gulf War Veterans. As predicted, a positive correlation between interleukin 6 and C-reactive protein was observed.

A Detoxification Intervention for Gulf War Illness: A Pilot Randomized Controlled Trial

Approximately 30% of the 700,000 US veterans of the 1990-1991 Persian Gulf War developed multiple persistent symptoms called Gulf War illness. While the etiology is uncertain, several toxic exposures including pesticides and chemical warfare agents have shown associations. There is no effective medical treatment. An intervention to enhance detoxification developed by Hubbard has improved quality of life and/or reduced body burdens in other cohorts. We evaluated its feasibility and efficacy in ill Gulf War (GW) veterans in a randomized, waitlist-controlled, pilot study at a community-based rehabilitation facility in the United States. Eligible participants (n = 32) were randomly assigned to the intervention (n = 22) or a four-week waitlist control (n = 10). The daily 4-6 week intervention consisted of exercise, sauna-induced sweating, crystalline nicotinic acid and other supplements. Primary outcomes included recruitment, retention and safety; and efficacy was measured via Veteran's Short Form-36 (SF-36) quality of life, McGill pain, multidimensional fatigue inventory questionnaires and neuropsychological batteries. Scoring of outcomes was blinded. All 32 completed the trial and 21 completed 3-month follow-up. Mean SF-36 physical component summary score after the intervention was 6.9 (95% CI; -0.3, 14.2) points higher compared to waitlist control and 11 of 16 quality of life, pain and fatigue measures improved, with no serious adverse events. Most improvements were retained after 3 months. The Hubbard regimen was feasible, safe and might offer relief for symptoms of GW illness.

The Neuroinflammatory Phenotype in a Mouse Model of Gulf War Illness is Unrelated to Brain Regional Levels of Acetylcholine as Measured by Quantitative HILIC-UPLC-MS/MS

Many veterans of the 1991 Persian Gulf War (GW) returned with a chronic multisymptom illness that has been termed Gulf War Illness (GWI). Previous GWI studies have suggested that exposure to acetylcholinesterase inhibitors (AChEIs) in theater, such as sarin and/or pesticides, may have contributed to the symptomatology of GWI. Additionally, concomitant high physiological stress experienced during the war may have contributed to the initiation of the GWI phenotype. Although inhibition of AChE leading to accumulation of acetylcholine (ACh) will activate the cholinergic anti-inflammatory pathway, the signature symptomatology of GWI has been shown to be associated with neuroinflammation. To investigate the relationship between ACh and neuroinflammation in discrete brain regions, we used our previously established mouse model of GWI, which combines an exposure to a high physiological stress mimic, corticosterone (CORT), with GW-relevant AChEIs. The AChEIs used in this study were diisopropyl fluorophosphate (DFP), chlorpyrifos oxon (CPO), and physostigmine (PHY). After AChEI exposure, ACh concentrations for cortex (CTX), hippocampus (HIP), and striatum (STR) were determined using hydrophilic interaction liquid chromatography with ultraperformance liquid chromatography-tandem-mass spectrometry (MS/MS). CORT pretreatment ameliorated the DFP-induced ACh increase in HIP and STR, but not CTX. CORT pretreatment did not significantly alter ACh levels for CPO and PHY. Further analysis of STR neuroinflammatory biomarkers revealed an exacerbated CORT + AChEI response, which does not correspond to measured brain ACh. By utilizing this new analytical method for discrete brain region analysis of ACh, this work suggests the exacerbated neuroinflammatory effects in our mouse model of GWI are not driven by the accumulation of brain region-specific ACh.

Four Decades after War: Incident Diabetes among Women Vietnam-Era Veterans in the HealthViEWS Study

OBJECTIVES

We analyzed long-term differences in incident diabetes associated with military service in a warzone among women who served during the Vietnam War era.

METHODS

For HealthViEWS, the largest later-life study of women Vietnam War-era U.S. veterans, a population-based retrospective cohort who served during 1965-1973 completed a health interview in 2011-2012. This cohort included women deployed to Vietnam, near Vietnam, or who served primarily in the United States. We hypothesized a warzone exposure gradient: Vietnam (highest exposure), near Vietnam, and the United States (lowest exposure). We used an extended Cox regression to test for differences in incident diabetes by location of wartime service.

RESULTS

Of 4,503 women in the analysis, 17.7% developed diabetes. Adjusting for demographics and military service characteristics, hazard of incident diabetes was significantly lower initially in the Vietnam group compared with the U.S. group (hazard ratio, 0.33; 95% confidence interval, 0.15-0.69). However, lower diabetes hazard in the Vietnam group was not constant over time; rather, hazard accumulated faster over time in the Vietnam group compared with the U.S. group (hazard ratio, 1.38; 95% confidence interval, 1.11-1.72). No significant difference in diabetes hazard was found between the near Vietnam and U.S. groups. Older age during military service, minority race/ethnicity, and lower military rank were associated with a higher diabetes hazard.

CONCLUSIONS

Women deployed to a warzone might have protective health factors that lower risk for diabetes early in their military career, but delivery systems for long-term health should consider that a lower risk for chronic diseases like diabetes can wane quickly in the decades that follow warzone service.

The prevalence of headaches, pain, and other associated symptoms in different Persian Gulf deployment periods and deployment durations

OBJECTIVES

This study aims to assess (1) the difference in the prevalence of headaches, pain, and other associated symptoms between Gulf War I (1990-1991) and Post-Gulf War I (1992-2015) veterans who served as active military personnel in the Persian Gulf and (2) how the durations of deployment may affect the prevalence of those symptoms.

METHODS

With institutional human subject committee approval, veterans who were accepted to the Gulf War Registry at the VA San Diego Healthcare System between July 2013 and June 2015 (N = 367) were included in this retrospective chart review study and grouped according to the Gulf War period they served under or how long they were deployed to the Persian Gulf. Chi-square was used for categorical data analyses and analysis of variance was conducted for continuous outcomes. All analyses were two-tailed, where applicable, with α = 0.05 and Bonferroni for pairwise group comparisons.

RESULTS

Veterans who served during Post-Gulf War I or both Gulf War I and Post-Gulf War I exhibited more pain and neurological symptoms than Gulf War I veterans (p = 0.005, p = 0.003). In addition, veterans who served ⩾12 months reported more overall pain symptoms and analgesic use than those who served less time (p < 0.001, p = 0.024).

CONCLUSION

The findings suggest that the length of deployment and Persian Gulf deployment period may play a role in acquiring headaches, pain, and other associated symptoms with increased analgesic consumption.

Influence of pain anticipation on brain activity and pain perception in Gulf War Veterans with chronic musculoskeletal pain

Anticipation of a painful experience can influence brain activity and increase sensitivity to experimental somatosensory stimuli in healthy adults, but this response is poorly understood among individuals with chronic musculoskeletal pain (CMP). Studies of brain and perceptual responses to somatosensory stimuli are used to make inferences about central nervous system dysfunction as a potential mechanism of symptoms. As such, we sought to (a) determine the influence of pain anticipation on pain-relevant brain regions and pain perception, and (b) characterize potential differences in these responses between Gulf War Veterans with CMP and matched healthy control (CO) Veterans. CMP (N = 30) and CO Veterans (N = 31) were randomized to conditions designed to generate expectations that either painful (pain) or nonpainful (no pain) stimuli would be administered. Brain responses to five nonpainful thermal stimuli were measured during fMRI, and each stimulus was rated for pain intensity and unpleasantness. In the pain condition, an incremental linear decrease in activity across stimuli was observed in the posterior cingulate cortex, cingulate cortex, and middle temporal gyrus. Further, in the pain condition, differential responses were observed between CMP and CO Veterans in the middle temporal gyrus. These findings indicate that brain responses to nonpainful thermal stimuli in Veterans with CMP are sensitive to pain anticipation, and we recommend accounting for the influence of pain anticipation in future investigations of central nervous system dysfunction in CMP.

Gulf War Illness: Unifying Hypothesis for a Continuing Health Problem

An estimated 25%⁻32% of veterans of the 1991 Gulf War continue to experience multiple unexplained health problems known as Gulf War Illness (GWI). GWI encompasses chronic pain, musculoskeletal weakness, headache, fatigue, cognitive deficits, alterations in mood, and numerous multi-system complaints. Most potential exposures implicated in GWI were not well documented but included varying levels of several neurotoxicants as well as the anticholinergic drug pyridostigmine bromide (PB), which was routinely taken as prophylaxis against the nerve agent soman. While some veterans also took chloroquine as an antimalarial agent, the literature suggests an association between receipt of multiple vaccinations prior to or during the conflict (perhaps combined with other exposures), and GWI. In-theater exposures may account for any single individual veteran's ill health but many veterans of the same era who were not deployed overseas also suffer the same or similar symptoms. The features of GWI also overlap with those of fibromyalgia, chronic fatigue syndrome and multiple chemical sensitivity, in all of which liver dysfunction has been documented, suggesting a unifying hypothesis. It is proposed that multiple vaccinations, with concurrent or subsequent exposure to PB or additional chemical insults of a liver-damaging nature, plausibly explain the pathogenesis and the observed chronicity of GWI. The suggested mechanism for GWI is thus a chemically-induced impaired liver function, with the spillage of stored vitamin A compounds ("retinoids") into the circulation in toxic concentrations, resulting in an endogenous chronic form of hypervitaminosis A. Implications of the hypothesis are briefly reviewed.

Corticosterone and pyridostigmine/DEET exposure attenuate peripheral cytokine expression: Supporting a dominant role for neuroinflammation in a mouse model of Gulf War Illness

Gulf War Illness (GWI) is a chronic multi-symptom disorder experienced by as many as a third of the veterans of the 1991 Gulf War; the constellation of "sickness behavior" symptoms observed in ill veterans is suggestive of a neuroimmune involvement. Various chemical exposures and conditions in theater have been implicated in the etiology of the illness. Previously, we found that GW-related organophosphates (OPs), such as the sarin surrogate, DFP, and chlorpyrifos, cause neuroinflammation. The combination of these exposures with exogenous corticosterone (CORT), mimicking high physiological stress, exacerbates the observed neuroinflammation. The potential relationship between the effects of OPs and CORT on the brain versus inflammation in the periphery has not been explored. Here, using our established GWI mouse model, we investigated the effects of CORT and DFP exposure, with or without a chronic application of pyridostigmine bromide (PB) and N,N-diethyl-meta-toluamide (DEET), on cytokines in the liver and serum. While CORT primed DFP-induced neuroinflammation, this effect was largely absent in the periphery. Moreover, the changes found in the peripheral tissues do not correlate with the previously reported neuroinflammation. These results not only support GWI as a neuroimmune disorder, but also highlight the separation between central and peripheral effects of these exposures.

Effect of deployment related experiences on sleep quality of German soldiers after return from an International Security Assistance Force (ISAF) mission to Afghanistan

The aim of the present study was to investigate the effect of experiencing potentially traumatic events during deployment on post-deployment sleep quality as measured by the Pittsburgh Sleep Quality Index (PSQI) and the Addendum for Post-Traumatic Stress Disorder (PTSD) of the Pittsburgh Sleep Quality Index (PSQI-A). Deployment related experiences were quantified on a standardised list of the Mental Health Advisory Team of the U.S. armed forces. The original sample consisted of 118 soldiers of the German armed forces who were deployed to Afghanistan for six months. The present analyses focused on data assessed after deployment (n = 70) and in a three-month follow-up (n = 51). Results indicate that immediately after return experiences during deployment had an independent significant effect on sleep quality but not three months later. Immediately after return depressive and stress symptoms significantly affected sleep quality while three months later somatic symptoms were significant. At both time points sleep prior to deployment was a significant predictor of sleep quality following deployment. Given the importance of sleep quality prior to deployment as a known independent risk factor for newly occurring mental disorders after deployment, these results underline the need to improve sleep quality already at an early stage.

DEVELOPMENT AND IMPLEMENTATION OF A NEW CONCEPT OF CRISIS SITUATIONS SYNDROME: "SYNDROME OF A HYBRID WAR"

The aim of our research was basis of the analysis and research of the current state and trends of emergence and development of crisis situations syndromes to identify their general and specific features inherent in specific crisis situations syndromes at the place where they occurred, factors that influenced their formation and the manifestations they characterized by. Materials and methods - analysis and systematization of data on the complex impact of stress factors and other manifestations of crisis situations on subjects who find themselves in a zone of military conflict / man-made or natural disaster; formulation of new concepts, strategies and tactics for work in crisis situations. Results. Common and specific features of the known syndromes of wars are found. It is proved that, by common characteristics, all syndromes of wars can be combined into a single basic category - crisis situations syndrome, which is divided by specific features into specific crisis situations syndromes at the place where they occurred, under what factors they were formed and the manifestations they characterize. A classification of post-traumatic stress disorders as a component of crisis situations syndromes by the mechanisms of their formation and a model of their formation are provided. Definitions are formulated; crisis syndrome and hybrid war syndrome are described. A working table has been developed for analysts for the differential diagnostic of “Crisis Situation Syndromes”. Conclusions. The technology of objective diagnostic, treatment and prevention of PTSD (post-traumatic stress disorder) and hybrid war syndrome is proposed, which includes the identification of possible etiological factors affecting the formation of crisis states syndromes with differentiation of impact factors, the actual identification with the formation of a differentiated approach to treatment, and prevention development of "coaching" techniques. The technology is based on a comprehensive psychological and ophthalmologic examination. It has been established that the “hybrid war syndrome” is formed both among combatants and non-combatants, for the first time in it the cognitive defeat, both of individual subjects and social groups is fully manifested. In addition, for the first time, in relation to other crisis syndromes, there are social group symptoms, the formation of migratory symptoms, the formation of specific PTSDs, etc.

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.

Dynamic cerebral autoregulation is impaired in Veterans with Gulf War Illness: A case-control study

Neurological dysfunction has been reported in Gulf War Illness (GWI), including abnormal cerebral blood flow (CBF) responses to physostigmine challenge. However, it is unclear whether the CBF response to normal physiological challenges and regulation is similarly dysfunctional. The goal of the present study was to evaluate the CBF velocity response to orthostatic stress (i.e., sit-to-stand maneuver) and increased fractional concentration of carbon dioxide. 23 cases of GWI (GWI+) and 9 controls (GWI) volunteered for this study. Primary variables of interest included an index of dynamic autoregulation and cerebrovascular reactivity. Dynamic autoregulation was significantly lower in GWI+ than GWI- both for autoregulatory index (2.99±1.5 vs 4.50±1.5, p = 0.017). In addition, we observed greater decreases in CBF velocity both at the nadir after standing (-18.5±6.0 vs -9.8±4.9%, p = 0.001) and during steady state standing (-5.7±7.1 vs -1.8±3.2%, p = 0.042). In contrast, cerebrovascular reactivity was not different between groups. In our sample of Veterans with GWI, dynamic autoregulation was impaired and consistent with greater cerebral hypoperfusion when standing. This reduced CBF may contribute to cognitive difficulties in these Veterans when upright.

Deployment of personnel to military operations: impact on mental health and social functioning

This Campbell systematic review examines the effects of deployment on mental health. The review summarizes evidence from 185 studies. All studies used observational data to quantify the effect of deployment. This review includes studies that evaluate the effects of deployment on mental health. A total of 185 studies were identified. However, only 40 of these were assessed to be of sufficient methodological quality to be included in the final analysis. The studies spanned the period from 1993 to 2017 and were mostly carried out in the USA, UK and Australia. The studies all had some important methodological weaknesses. None of the included studies used experimental designs (random assignment). Deployment to military operations negatively affects the mental health functioning of deployed military personnel. For assessments taken more than 24 months since exposure, we consistently found adverse effects of deployment on all mental health domains (PTSD, depression, substance abuse/dependence, and common mental disorders), particularly on PTSD. For assessments taken less than 24 months (or a variable number of months since exposure) the evidence was less consistent and in many instances inconclusive.

Plain language summary

Deployment to military operations negatively affects the mental health functioning of deployed military personnel: While additional research is needed, the current evidence strongly supports the notion that deployment negatively affects mental health functioning of deployed military personnel.What is this review about?: When military personnel are deployed to military operations abroad they face an increased risk of physical harm, and an increased risk of adverse shocks to their mental health.The primary condition under consideration is deployment to an international military operation. Deployment to a military operation is not a uniform condition; rather, it covers a range of scenarios. Military deployment is defined as performing military service in an operation at a location outside the home country for a limited time period, pursuant to orders.The review included studies that reported outcomes for individuals who had been deployed. This review looked at the effect of deployment on mental health outcomes. The mental health outcomes are: post-traumatic stress disorder (PTSD), major depressive disorder (MDD), common mental disorders (depression, anxiety and somatisation disorders) and substance-related disorders.By identifying the major effects of deployment on mental health and quantifying these effects, the review can inform policy development on deployment and military activity as well as post-deployment support for veterans. In this way the review enables decision-makers to prioritise key areas.What are the main findings of this review?: What studies are included?: This review includes studies that evaluate the effects of deployment on mental health. A total of 185 studies were identified. However, only 40 of these were assessed to be of sufficient methodological quality to be included in the final analysis. The studies spanned the period from 1993 to 2017 and were mostly carried out in the USA, UK and Australia. The studies all had some important methodological weaknesses. None of the included studies used experimental designs (random assignment).Does deployment have an effect on mental health?: Deployment to military operations negatively affects the mental health functioning of deployed military personnel. For assessments taken more than 24 months since exposure, we consistently found adverse effects of deployment on all mental health domains (PTSD, depression, substance abuse/dependence, and common mental disorders), particularly on PTSD. For assessments taken less than 24 months (or a variable number of months since exposure) the evidence was less consistent and in many instances inconclusive.What do the findings of this review mean?: The odds of screening positive for PTSD and depression were consistently high in the longer term. This suggests that efforts should be increased to detect and treat mental disorders, as effects may be long-lasting.Overall the risk of bias in the majority of included studies was high. While it is difficult to imagine a randomised study design to understand how deployment affects mental health, other matters such as changes to personnel policy, or unanticipated shocks to the demand for military personnel, could potentially be a rich source of quasi-experimental variation.How up-to-date is this review?: The review authors searched for studies up to 2017. This Campbell systematic review was published in March 2018.

Executive summary

BACKGROUND: When military personnel are deployed to military operations abroad they face an increased risk of physical harm, and an increased risk of adverse shocks to their mental health. Research suggests that the increased risk to mental health is mainly due to the hazards of war, combat exposure: firing weapons, road side bombs, seeing fellow soldiers, friends, civilians, and enemies being injured, maimed or killed. These experiences may lead to severe mental stress. The adverse impact on mental health is the psychological cost of war, and it is of interest to policymakers to learn the magnitude of these effects. This review sets out to synthesise available evidence about the consequences of deployment for deployed military personnel in the mental health and social functioning domains.OBJECTIVES: The objective of this review isto synthesise the consequences of deployment to military operation on the mental health and social functioning of deployed military personnel.SEARCH METHODS: We searched electronic databases, grey literature, and references from primary studies and related reviews. No language or date restrictions were applied to the searches. We searched the following electronic databases: Academic Search Elite, Cochrane Library, EMBASE, ERIC, MEDLINE, PsycINFO, Science Citation Index, Social Science Citation Index, SocINDEX, as well as the Nordic platforms: bibliotek.dk, BIBSYS, and LIBRIS. The conclusions of this review are based on the most recent searches performed. The last search was performed in April 2017.SELECTION CRITERIA: Primary studies had to meet the following inclusion criteria: Participants: The participants should be military personnel.Intervention: The condition should be deployment to a military operation.Comparison: The relevant comparisons were either comparing a) deployed military personnel to non-deployed military personnel, b) deployed military personnel to military personnel deployed elsewhere, for example personnel deployed to non-combat operations, c) military personnel deployed to the same operation but stratified by combat exposure.Outcomes: The study should report on one or more mental health outcomes, and/or social functioning for the deployed participants. In particular studies should report on one or more of the following mental health outcomes: PTSD, major depression, substance abuse or dependence (including alcohol), and common mental disorders (depression and anxiety disorders). The following social functioning outcomes were relevant: employment, and homelessness.Study Designs: Both experimental and quasi-experimental designs with a comparison group were eligible for inclusion in the review. Studies were excluded if they: Reported on deployments taking place before 1989.Used a within group pre-post study design.Did not report on at least one of the mental health or social functioning outcomes. DATA COLLECTION AND ANALYSIS: The total number of potentially relevant studies constituted31,049records. A total of 185 studies met the inclusion criteria and were critically appraised by the review authors. The final selection of 185 studies was from 13 different countries.Forty eight of the 185 studies did not report effect estimates or provide data that would allow the calculation of an effect size and standard error. Fifty four studies were excluded because of overlapping samples. The majority of those studies were from USA but the main reason for not using studies from USA in the synthesis was lack of information to calculate an effect size. Nearly half the studies from the UK could not be used in the synthesis due to overlap of data samples. Forty three studies were judged to have a very high risk of bias (5 on the scale) and, in accordance with the protocol, we excluded these from the data synthesis on the basis that they would be more likely to mislead than inform., Thus a total of 40 studies, from five different countries, were included in the data synthesis.Random effects models were used to pool data across the studies. We used the odds ratio. Pooled estimates were weighted with inverse variance methods, and 95% confidence intervals were calculated. The meta-analyses were carried out by time since exposure (short, medium, long, and other time since exposure) and by type of comparison (deployed versus non-deployed, all deployed but stratified by either combat operations versus non-combat operations, or stratified by combat exposure). We performed single factor subgroup analysis. The assessment of any difference between subgroups was based on 95% confidence intervals. Funnel plots were used to assess the possibility of publication bias. Sensitivity analysis was used to evaluate whether the pooled effect sizes were robust across components of methodological quality.MAIN RESULTS: The findings were mixed, depending on the outcome, the time since exposure and the approach (deployed versus non-deployed termed absolute or stratified by extent of combat termed relative) used to investigate the effect. It was not possible to analyse the outcomes homelessness and employment. All studies that could be used in the data synthesis reported on the impact of deployment on mental health; PTSD, depression, substance use or common mental disorder.For assessments taken less than 24 months since exposure the evidence was inconclusive either because too few studies reported results in the short and medium term and/or the degree of heterogeneity between studies was large.For assessments taken at other time points (a variable number of months since exposure) the evidence was inconclusive for the relative comparisons due to either too few studies or a substantial degree of heterogeneity between studies. For the absolute comparison the analysis of common mental disorder was inconclusive, whereas the average effects of PTSD and depression were positive and statistically significant (PTSD odds ratio (OR) was 1.91 (95% confidence interval (CI): 1.28 to 2.85) and OR=1.98 (95% CI: 1.05 to 3.70) for depression). The analysis concerning substance use indicated that deployed participants did not have higher odds of screening positive for substance use compared to non-deployed participants (OR=1.15 (95% CI: 0.98 to 1.36)).For assessments taken more than 24 months post exposure, meta-analyses indicated that the odds of screening positive for PTSD, depression, substance use and common mental disorder were higher for participants in the deployed group compared to participants in the group that were not deployed (PTSD OR=3.31 (95% CI: 2.69 to 4.07), OR=2.19 (95% CI: 1.58 to 3.03) for depression, OR=1.27 (95% CI: 1.15 to 1.39) for substance use, and OR=1.64 (95% CI: 1.38 to 1.96) for common mental disorder). Likewise, participants reporting high combat exposure had higher odds of screening positive for PTSD and depression than participants reporting lower exposure for long term assessments (PTSD OR=3.05 (95% CI: 1.94 to 4.80) and OR=1.81 (95% CI: 1.28 to 2.56) for depression). The analyses of substance use and common mental disorder were inconclusive due to too few studies.On the basis of the prevalence of mental health problems in pre-deployed or non-deployed population based comparison sampleswe would therefore expect the long term prevalence of PTSD in post-deployed samples to be in the range 6.1 - 14.9%, the long term prevalence of depression to be in the range from 7.6% to 18%, the long term prevalence of substance use to be in the range from 2.4% to 17.5% and the prevalence of common mental disorder to be in the range from 10% to 23%.Sensitivity analyses resulted in no appreciable change in effect size, suggesting that the results are robust.It was only possible to assess the impact of two types of personnel characteristics (branch of service and duty/enlistment status) on the mental health outcomes. We found no evidence to suggest that the effect of deployment on any outcomes differ between these two types of personnel characteristics.AUTHORS' CONCLUSIONS: Deployment to military operations negatively affects the mental health functioning of deployed military personnel. We focused on the effect of deployment on PTSD (post-traumatic stress disorder), depression, substance abuse/dependence, and common mental disorders (depression and anxiety disorders). For assessments taken less than 24 months (or a variable number of months since exposure) the evidence was less consistent and in many instances inconclusive. For assessments taken more than 24 months since exposure, we consistently found adverse effects of deployment on all domains, particularly on PTSD. There is increased political awareness of the need to address post deployment mental health problems. The odds of screening positive for PTSD and depression were consistently high in the longer term. This suggests that efforts should be increased to detect and treat mental disorders, as effects may be long lasting. Mental illness is of particular concern in the military for operational reasons, but they may be hard to detect in the military setting because a military career is intimately linked with mental and physical strength.It was not possible to examine a number of factors which we had reason to expect would impact on the magnitude of the effect. This would have been particularly relevant from a policy perspective because these are direct parameters that one could use to optimally "organize" deployment in order to minimize impacts on mental health functioning.While additional research is needed, the current evidence strongly supports the notion that deployment negatively affects mental health functioning of deployed military personnel. The next step is to begin to examine preventive measures and policies for organizing deployment, in order to minimize the effects on mental health.