Declining autozygosity over time: An exploration in over 1 million individuals from three diverse cohorts.

Previous studies have hypothesized that autozygosity is decreasing over generational time. However, these studies were limited to relatively small samples (n < 11,000) lacking in diversity, which may limit the generalizability of their findings. We present data that partially support this hypothesis from three large cohorts of diverse ancestries, two from the US (All of Us, n = 82,474; the Million Veteran Program, n = 622,497) and one from the UK (UK Biobank, n = 380,899). Our results from a mixed-effect meta-analysis demonstrate an overall trend of decreasing autozygosity over generational time (meta-analyzed slope = -0.029, SE = 0.009, p = 6.03e-4). On the basis of our estimates, we would predict FROH to decline 0.29% for every 20-year increase in birth year. We determined that a model including an ancestry-by-country interaction term fit the data best, indicating that ancestry differences in this trend differ by country. We found further evidence to suggest a difference between the US and UK cohorts by meta-analyzing within country, observing a significant negative estimate in the US cohorts (meta-analyzed slope = -0.058, SE = 0.015, p = 1.50e-4) but a non-significant estimate in the UK (meta-analyzed slope = -0.001, SE = 0.008, p = 0.945). The association between autozygosity and birth year was substantially attenuated when accounting for educational attainment and income (meta-analyzed slope = -0.011, SE = 0.008, p = 0.167), suggesting they may partially account for decreasing autozygosity over time. Overall, we demonstrate decreasing autozygosity over time in a large, modern sample and speculate that this trend can be attributed to increases in urbanization and panmixia and differences in sociodemographic processes lead to country-specific differences in the rate of decline.

Modeling the longitudinal changes of ancestry diversity in the Million Veteran Program.

BACKGROUND: The Million Veteran Program (MVP) participants represent 100 years of US history, including significant social and demographic changes over time. Our study assessed two aspects of the MVP: (i) longitudinal changes in population diversity and (ii) how these changes can be accounted for in genome-wide association studies (GWAS). To investigate these aspects, we divided MVP participants into five birth cohorts (N-range = 123,888 [born from 1943 to 1947] to 136,699 [born from 1948 to 1953]). RESULTS: Ancestry groups were defined by (i) HARE (harmonized ancestry and race/ethnicity) and (ii) a random-forest clustering approach using the 1000 Genomes Project and the Human Genome Diversity Project (1kGP + HGDP) reference panels (77 world populations representing six continental groups). In these groups, we performed GWASs of height, a trait potentially affected by population stratification. Birth cohorts demonstrate important trends in ancestry diversity over time. More recent HARE-assigned Europeans, Africans, and Hispanics had lower European ancestry proportions than older birth cohorts (0.010 < Cohen's d < 0.259, p < 7.80 × 10-4). Conversely, HARE-assigned East Asians showed an increase in European ancestry proportion over time. In GWAS of height using HARE assignments, genomic inflation due to population stratification was prevalent across all birth cohorts (linkage disequilibrium score regression intercept = 1.08 ± 0.042). The 1kGP + HGDP-based ancestry assignment significantly reduced the population stratification (mean intercept reduction = 0.045 ± 0.007, p < 0.05) confounding in the GWAS statistics. CONCLUSIONS: This study provides a characterization of ancestry diversity of the MVP cohort over time and compares two strategies to infer genetically defined ancestry groups by assessing differences in controlling population stratification in genome-wide association studies.

Veteran Beliefs About the Causes of Gulf War Illness and Expectations for Improvement.

BACKGROUND: Individuals' beliefs about the etiology of persistent physical symptoms (PPS) are linked to differences in coping style. However, it is unclear which attributions are related to greater expectations for improvement. METHOD AND RESULTS: A cross-sectional regression analysis (N = 262) indicated that Veterans with Gulf War Illness (GWI) who attributed their GWI to behavior, (e.g., diet and exercise), had greater expectations for improvement (p = .001) than those who attributed their GWI to deployment, physical, or psychological causes (p values > .05). CONCLUSIONS: Findings support the possible clinical utility of exploring perceived contributing factors of PPS, which may increase perceptions that improvement of PPS is possible. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02161133.

Relationship between clinician documented blast exposure and pulmonary function: a retrospective chart review from a national specialty clinic.

BACKGROUND: Service member exposure to explosive blast overpressure waves is common with considerable attention to traumatic brain injury (TBI) and neuropsychological sequalae. Less is known about the impacts on the respiratory system, particularly long-term effects, despite vulnerability to overpressure. Using a national registry, we previously observed an independent relationship between self-reported blast exposure and respiratory symptoms; however, the impact on objective measures of pulmonary function is poorly understood. METHODS: 307 Veterans referred to our national specialty center for post-deployment health concerns underwent a comprehensive multi-day evaluation that included complete pulmonary function testing (PFT), occupational and environmental medicine history, neuropsychological or psychological evaluation. We developed an a priori chart abstraction process and template to classify Veterans into blast exposure groups: (1) none, (2) single-mild, or (3) multiple-mild. This template focused primarily on clinician documented notes of blast related TBI that were used as proxy for blast overpressure injury to thorax. PFT variables characterizing flow (FEV1%; %∆FEV1), volume (TLC%), diffusion (DLCO%) and respiratory mechanics (forced oscillometry) were selected for analysis. RESULTS: Veterans (40.5 ± 9.7 years; 16.3% female) were referred 8.6 ± 3.6 years after their last deployment and presented with considerable comorbid conditions and health problems (e.g., 62% post-traumatic stress, 55% dyspnea). After chart abstraction, Veterans were assigned to none (n = 208), single mild (n = 52) and multiple mild (n = 47) blast exposure groups. Among the blast exposed, clinicians documented 73.7% were < 50 m from the blast and 40.4% were physically moved by blast. PFT outcome measures were similar across all groups (p value range: 0.10-0.99). CONCLUSIONS: In this referred sample of deployed Veterans, PFT measures of flow, volume, diffusion, and respiratory mechanics were not associated with clinician documented blast exposure per the retrospective chart abstraction methodology applied. Yet, these clinical findings suggest future research should determine and assess distinction between Veteran recollections of perceived blast experiences versus overpressure wave exposure to the respiratory system.

Smoking Status and Factors associated with COVID-19 In-Hospital Mortality among US Veterans.

INTRODUCTION: The role of smoking in risk of death among patients with COVID-19 remains unclear. We examined the association between in-hospital mortality from COVID-19 and smoking status and other factors in the United States Veterans Health Administration (VHA). METHODS: This is an observational, retrospective cohort study using the VHA COVID-19 shared data resources for February 1 to September 11, 2020. Veterans admitted to the hospital who tested positive for SARS-CoV-2 and hospitalized by VHA were grouped into Never (as reference, NS), Former (FS), and Current smokers (CS). The main outcome was in-hospital mortality. Control factors were the most important variables (among all available) determined through a cascade of machine learning. We reported adjusted odds ratios (aOR) and 95% confidence intervals (95%CI) from logistic regression models, imputing missing smoking status in our primary analysis. RESULTS: Out of 8 667 996 VHA enrollees, 505 143 were tested for SARS-CoV-2 (NS = 191 143; FS = 240 336; CS = 117 706; Unknown = 45 533). The aOR of in-hospital mortality was 1.16 (95%CI 1.01, 1.32) for FS vs. NS and 0.97 (95%CI 0.78, 1.22; p > .05) for CS vs. NS with imputed smoking status. Among other factors, famotidine and nonsteroidal anti-inflammatory drugs (NSAID) use before hospitalization were associated with lower risk while diabetes with complications, kidney disease, obesity, and advanced age were associated with higher risk of in-hospital mortality. CONCLUSIONS: In patients admitted to the hospital with SARS-CoV-2 infection, our data demonstrate that FS are at higher risk of in-hospital mortality than NS. However, this pattern was not seen among CS highlighting the need for more granular analysis with high-quality smoking status data to further clarify our understanding of smoking risk and COVID-19-related mortality. Presence of comorbidities and advanced age were also associated with increased risk of in-hospital mortality. IMPLICATIONS: Veterans who were former smokers were at higher risk of in-hospital mortality compared to never smokers. Current smokers and never smokers were at similar risk of in-hospital mortality. The use of famotidine and nonsteroidal anti-inflammatory drugs (NSAIDs) before hospitalization were associated with lower risk while uncontrolled diabetes mellitus, advanced age, kidney disease, and obesity were associated with higher risk of in-hospital mortality.

Assessing Change in Participation in Clinical Evaluations of Deployed Veterans with Medically Unexplained Symptoms.

Many deployed veterans experience issues reintegrating into civilian life. Addressing this in a clinical setting can prove challenging; however, assessing participation, defined as involvement in a life situation by the World Health Organization's International Classification of Functioning, Disability and Health, may be helpful. The Community Reintegration of Injured Service Members-Computer Adaptive Test (CRIS-CAT) is a measure of participation developed and validated in veteran populations. The War Related and Illness and Injury Study Center, which provides comprehensive evaluations to veterans with medically unexplained deployment-related concerns, used the CRIS-CAT as part of their social work evaluations during these visits and follow-up telephone calls. This retrospective review of clinical data examines the link between participation as assessed by the CRIS-CAT and factors that are mutable (such as relationships with others) and immutable (personal characteristics) as assessed in the social work evaluation over 12 months. The findings indicate that these veteran patients did not experience change in their participation as measured by the CRIS-CAT. Multivariable regression models demonstrated relationships only between change in CRIS-CAT scales and baseline scores and race. Article concludes by discussing lessons learned from this evaluation of the utility of the CRIS-CAT in clinical care and in longitudinal evaluation.

Risk for depression and suicidal ideation among food insecure US veterans: data from the National Health and Nutrition Examination Study.

BACKGROUND: Suicide and food insecurity (i.e., lack of access to food) are two major issues that affect US Veterans. PURPOSE: Using a US-based sample, we evaluated the association between food insecurity and suicidal ideation among Veterans. Because depression often precedes suicide, we also examined the association between food insecurity and depression. METHODS: Using data from 2630 Veterans who participated in the National Health and Nutrition Examination Survey 2007-2016, we conducted an adjusted linear regression model to evaluate the association between food insecurity (measured using 18-item Household Food Security Survey) and depression (measured using PHQ-9) and an adjusted binary logistic regression model to evaluate the association between food insecurity and suicidal ideation (measured using PHQ-9 Question 9). Models were adjusted for gender, age, income-to-poverty ratio, race/ethnicity, and education level. RESULTS: Of the sample, 11.5% were food insecure, depression scores averaged 2.86 (SD = 4.28), and 3.7% endorsed suicidal ideation. Veterans with marginal (ß = 0.68, 95%CI [0.09,1.28]), low (ß = 1.38, 95%CI [0.70,2.05]) or very low food security (ß = 3.08, 95%CI [2.34, 3.83]) had significantly increased depression scores compared to food secure Veterans. Veterans with low (OR = 2.15, 95%CI [1.08, 4.27]) or very low food security (OR = 3.84, 95%CI [2.05, 7.20]) had significantly increased odds for suicidal ideation compared to food secure Veterans. CONCLUSION: Food insecurity in Veterans is associated with increased depression symptoms and suicidal ideation. This association strengthens as food insecurity worsens. Veterans with food insecurity should be screened for depression and suicidal ideation. Simultaneously, depression treatment plans and suicide prevention programs should consider basic needs like food security.

Measurement Properties of the MPAI-4 in Veterans With mTBI.

OBJECTIVES: To determine whether the measurement properties of the Mayo-Portland Adaptability Inventory Version 4 (MPAI-4) and its participation index (M2PI), which have been adopted as 2 outcome measures in the Veterans Health Administration (VHA) National Polytrauma Rehabilitation Systems of Care, are adequate in veterans with mild traumatic brain injury (mTBI). DESIGN: Cross-sectional. SETTING: Outpatient rehabilitation. PARTICIPANTS: Postdeployment veterans with blast-related mTBI (N=177). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Mayo-Portland Adaptability Inventory Version 4 (MPAI-4) and Community Integration Questionnaire (CIQ). RESULTS: The unidimensional factor structure of the MPAI-4 total and 3 index scores (abilities, adjustment, participation) were confirmed. Eight of the 30 items were removed for violating monotonicity (6 items) and exceeding Rasch infit (2 items). The rating scale was collapsed from 5 to 3 ratings because of structure issues. The remaining 22 MPAI-4 items demonstrated excellent item/person reliability (0.98/0.91) and separated person ability into 4 strata. Two of the MPAI-4 index scores (abilities and adjustment) had good measurement properties. The third index, M2PI, retained only 3 items that had adequate person reliability (0.75) but separated person ability into only 2 strata. A significant but fair association with the CIQ was demonstrated with the modified MPAI-4. CONCLUSIONS: The MPAI-4 has been validated in moderate to severe traumatic brain injury but required modification when used in active military personnel with mTBI. We also identified the need for modification of the MPAI-4 to support adequate psychometrics when measuring outcomes in veterans with mTBI. Additional validation of the M2PI is needed in veterans and active military personnel with mTBI, to determine whether the M2PI should continue to be used as an outcome measure in the VHA polytrauma rehabilitation systems.

Interrelationships between symptom burden and health functioning and health care utilization among veterans with persistent physical symptoms.

BACKGROUND: Between 10 and 50% of primary care patients present with persistent physical symptoms (PPS). Patients with PPS tend to utilize excessive or inappropriate health care services, while being stuck in a deleterious cycle of inactivity, deconditioning, and further worsening of symptoms and disability. Since military deployment (relative to non-deployment) is associated with greater likelihood of PPS, we examined the interrelationships of health care utilization, symptom burden and functioning among a sample of recently deployed Veterans with new onset persistent physical symptoms. METHODS: This study analyzed a cohort of 790 U.S. soldiers who recently returned from deployment to Iraq or Afghanistan. Data for this analysis were obtained at pre- and post-deployment. We used moderation analyses to evaluate interactions between physical symptom burden and physical and mental health functioning and four types of health care utilization one-year after deployment, after adjusting for key baseline measures. RESULTS: Moderation analyses revealed significant triple interactions between physical symptom burden and health functioning and: primary care (F = 3.63 [2, 303], R2Δ = .02, p = 0.03), specialty care (F = 6.81 [2, 303] R2Δ =0.03, p < .001), allied therapy care (F = 3.76 [2, 302], R2Δ = .02, p = 0.02), but not mental health care (F = 1.82 [1, 303], R2Δ = .01, p = .16), one-year after deployment. CONCLUSIONS: Among U.S. Veterans with newly emerging persistent physical symptoms one-year after deployment, increased physical symptom burden coupled with decreased physical and increased mental health functioning was associated with increased medical care use in the year after deployment. These findings support whole health initiatives aimed at improving health function/well-being, rather than merely symptom alleviation.

Variations in VA and Medicare Use Among Veterans With Diabetes: Impacts on Ambulatory Care Sensitive Conditions Hospitalizations for 2008, 2009, and 2010.

INTRODUCTION: VA and Medicare use among older Veterans has been considered fragmented care, however, it may represent access to needed care. METHODS: The population studied were Veterans with diabetes, age 66 years and older, dually enrolled in VA and Medicare. DATA SOURCE/STUDY SETTING: We conducted a dynamic retrospective cohort study with 2008, 2009, and 2010 as the outcome years (Ambulatory Care Sensitive Conditions Hospitalization (ACSC-H) or not). We analyzed administrative data to identify comorbidities; ambulatory care utilization to identify variations in use before hospitalization. We linked 2007 primary care (PC) survey data to assess if organizational factors were associated with ACSC-H. MEASURES AND ANALYSIS: We identified ACSC-Hs using a validated definition. We categorized VA/Medicare use as: single system; dual system: supplemental specialty care use; or primary care use. Using hierarchical logistic regression models, we tested for associations between VA/Medicare use, organizational characteristics, and ACSC-H controlling for patient-level, organizational-level, and area-level characteristics. RESULTS: Our analytic population was comprised of 210,726 Medicare-eligible Veterans; more than one quarter had an ACSC-H. We found that single system users had higher odds of ACSC-H compared with dual system specialty supplemental care use (odds ratio, 1.14; 95% confidence interval, 1.09-1.20), and no significant difference between dual-system users. Veterans obtaining care at sites where PC leaders reported greater autonomy (eg, authority over personnel issues) had lower odds of ACSC-H (odds ratio, 0.74; 95% confidence interval, 0.59-0.92). DISCUSSION: Our findings suggest that earlier assumptions about VA/Medicare use should be weighed against the possibility that neither VA nor Medicare may address complex Veterans' health needs. Greater PC leader autonomy may allow for tailoring of care to match local clinical contexts.

Coping with Medically Unexplained Physical Symptoms: the Role of Illness Beliefs and Behaviors.

BACKGROUND: Medically unexplained syndromes (MUS) are both prevalent and disabling. While illness beliefs and behaviors are thought to maintain MUS-related disability, little is known about which specific behavioral responses to MUS are related to disability or the way in which beliefs and behaviors interact to impact functioning. The purpose of the present study was to examine the relationship between illness beliefs and disability among patients with MUS, and assess the extent to which behaviors mediate this relationship. METHODS: The study examined data from the baseline assessment of a multi-site randomized controlled trial (RCT). Participants were 248 veterans with MUS. Illness beliefs, behavioral responses to illness, and disability were assessed through self-report questionnaire. Data were analyzed using mediation analysis. RESULTS: Threat-related beliefs predicted greater disability through decreased activity and increased practical support seeking. Protective beliefs predicted less disability through reductions in all-or-nothing behavior and limiting behavior. CONCLUSIONS: These outcomes suggest that all-or-nothing behavior, limiting behavior, and practical support seeking are important in the perpetuation of disability among those with MUS. This has implications for improving MUS treatment by highlighting potential treatment targets. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02161133.

Helpful ways providers can communicate about persistent medically unexplained physical symptoms.

BACKGROUND: Communication between patients and providers about persistent "medically unexplained" physical symptoms (MUS) is characterized by discordance. While the difficulties are well documented, few studies have examined effective communication. We sought to determine what veterans with Gulf War Illness (GWI) perceive as the most helpful communication from their providers. Veterans with GWI, a type of MUS, have historically had complex relationships with medical providers. Determining effective communication for patients with particularly complex relationships may help identify the most critical communication elements for all patients with MUS. METHODS: Two hundred and-ten veterans with GWI were asked, in a written questionnaire, what was the most useful thing a medical provider had told them about their GWI. Responses were coded into three categories with 10 codes. RESULTS: The most prevalent helpful communication reported by patients was when the provider offered acknowledgement and validation (N = 70). Specific recommendations for managing GWI or its symptoms (N = 48) were also commonly reported to be helpful. In contrast, about a third of the responses indicated that nothing about the communication was helpful (N = 63). There were not differences in severity of symptoms, disability or healthcare utilization between patients who found acknowledgement and validation, specific recommendations or nothing helpful. CONCLUSIONS: Previous research has documented the discord between patients and providers regarding MUS. This study suggests that most patients are able to identify something helpful a provider has said, particularly acknowledgement and validation and specific treatment recommendations. The findings also highlight missed communication opportunities with a third of patients not finding anything helpful.

Medically Unexplained Physical Symptoms: What They Are and Why Counseling Psychologists Should Care about Them.

Medically unexplained symptoms and syndromes (MUS) affect the health of 20%-30% of patients seen in primary care. Optimally, treatment for these patients requires an interdisciplinary team consisting of both primary care and mental health providers. By developing an expertise in MUS, counseling psychologists can improve the care of patients with MUS who are already in their practice, expand the number of patients they help, and enhance the integration of counseling psychology into the broader medical community. Additionally, counseling psychologists' expertise in culture, attunement to therapeutic processes, and our focus on prioritizing patients' perspectives and quality of life can fill the gap in research on MUS and bringing increased attention to counseling psychologists' unique contributions to health service delivery.

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.

Psychometric Properties of 2 Participation Measures in Veterans With Mild Traumatic Brain Injury.

OBJECTIVE: To compare the psychometric properties of 2 commonly used participation measures: the Community Reintegration of Service Members (CRIS) and the Participation Assessment with Recombined Tools-Objective (PART-O) in veterans with mild traumatic brain injury (mTBI). DESIGN: Data were collected from 2 cross-sectional observation studies conducted in 2 Veterans Affairs medical centers. SETTING: Questionnaires were completed in-person or by mail. PARTICIPANTS: Veterans with mTBI (N=201) were recruited from the Michael E. DeBakey Veterans Affairs Medical Center in Houston (n=94) and the Malcom Randall North Florida/South Georgia Veterans Health System (n=107). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: CRIS and PART-O. RESULTS: We conducted Rasch analysis on the PART-O and on 3 subscales of the CRIS (extent of participation, perceived limitation, and satisfaction). For PART-O, results showed PART-O has questionable unidimensionality. For both instruments, some rating categories were underused, and rating scales did not advance accordingly. Compared with PART-O, the CRIS was able to distinguish more categories of person's ability (>5 vs 2 for PART-O) and had better internal consistency as indicated by higher Cronbach α (.96-.98 vs .65 for PART-O). CONCLUSIONS: To capture participation unique to veterans with mTBI, CRIS has greater potential to detect a change in participation and is therefore recommended over PART-O. Rating scales of both instruments, however, need further refinement. We suggest future studies examine collapsed rating categories and use qualitative methods to redefine categories.

Longitudinal relationship between onset of physical symptoms and functional impairment.

Patients with chronic physical symptoms (e.g., chronic pain) often have significant functional impairment (i.e., disability). The fear avoidance model is the dominant theoretical model of how the relationship between chronic physical symptoms and functional impairment develops and proposes a cyclical/bidirectional relationship. There has never been a definitive test of the proposed bi-directional relationship. The current study followed 767 Operation Enduring Freedom/Operation Iraqi Freedom soldiers from pre-deployment, when they were relatively healthy, to 1 year after deployment, when it was anticipated that symptoms would increase or develop. Over the four assessment time points, physical symptom severity consistently predicted worse functional impairment at the subsequent time point. Functional impairment did not show a consistent relationship with worsening of physical symptom severity. These findings suggest that changes to functional impairment do not have a short-term impact on physical symptom severity.

State-Level Variability in Veteran Reliance on Veterans Health Administration and Potentially Preventable Hospitalizations: A Geospatial Analysis.

Most Veterans who use the Veterans Health Administration (VHA) also utilize private-sector health care providers. To better inform local and regional health care planning, we assessed the association between reliance on VHA ambulatory care and total and system-specific preventable hospitalization rates (PHRs) at the state level. We conducted a retrospective dynamic cohort study using Veterans with diabetes mellitus, aged 66 years or older, and dually enrolled in VHA and Medicare parts A and B from 2004 to 2010. While controlling for median age and proportion of males, we measured the association between reliance on VHA ambulatory care and PHRs at the state level using multivariable ordinary least square regression, geographically weighted regression, and generalized additive models. We measured geospatial patterns in PHRs using global Moran's I and univariate local indicator spatial analysis. Approximately 30% of hospitalized Veterans experienced a preventable hospitalization. Reliance on VHA ambulatory care at the state level ranged from 13.92% to 67.78% and was generally not associated with PHRs. Geospatial analysis consistently identified a cluster of western states with low PHRs from 2006 to 2010. Given the generally low reliance on VHA ambulatory care and lack of association between this reliance and PHRs, policy changes to improve Veterans' health care outcomes should address private-sector care in addition to VHA care.

Airborne hazards exposure and respiratory health of Iraq and Afghanistan veterans.

More than 2.6 million military personnel have been deployed to recent conflicts in Iraq and Afghanistan and were likely exposed to a variety of airborne hazards during deployment. Despite several epidemiologic reports of increased respiratory symptoms, whether or not these respiratory illnesses lead to reductions in lung function and/or specific pulmonary disease is unclear. We reviewed data published from 2001 to 2014 pertaining to respiratory health in military personnel deployed to Iraq and Afghanistan and found 19 unique studies. Study designs were primarily retrospective and observational in nature with patient symptom reporting and medical encounter data as primary outcome measures. Two case series reported on rare respiratory diseases, and one performed a standardized evaluation of new-onset respiratory symptoms. Respiratory outcomes in relation to proximity to a specific air pollution source (i.e., smoke from burning trash and sulfur mine fire) were described in 2 separate studies. Only 2 longitudinal investigations were identified comparing pre- and postdeployment measurement of exercise capacity. In summary, published data based on case reports and retrospective cohort studies suggest a higher prevalence of respiratory symptoms and respiratory illness consistent with airway obstruction. However, the association between chronic lung disease and airborne hazards exposure requires further longitudinal research studies with objective pulmonary assessments.