A Prospective Study of Mortality and Trauma-Related Risk Factors Among a Nationally Representative Sample of Vietnam Veterans.

Because Vietnam veterans comprise the majority of all living veterans and most are now older adults, the urgency and potential value of studying the long-term health effects of service in the Vietnam War, including effects on mortality, is increasing. The present study is the first prospective mortality assessment of a representative sample of Vietnam veterans. We used one of the longest follow-up periods to date (spanning older adulthood) and conducted one of the most comprehensive assessments of potential risk factors. Vital status and cause of death were ascertained for the 1,632 veterans who fought in the Vietnam theater (hereafter referred to as theater veterans) and for 716 Vietnam War-era veterans (hereafter referred to as era veterans) who participated in the National Vietnam Veterans Readjustment Study (1987-2011). As of April 2011, 16.0% (95% confidence interval: 13.1, 19.0) of all Vietnam veterans who were alive in the 1980s were deceased. Male theater veterans with a high probability of posttraumatic stress disorder (PTSD) were nearly 2 times more likely to have died than were those without PTSD, even after adjustment for sociodemographic and other characteristics. A high level of exposure to war zone stress was independently associated with mortality for both male and female theater veterans after adjustment for sociodemographic characteristics, PTSD, and physical comorbid conditions. Theater veterans with a high level of exposure to war zone stress and a high probability of PTSD had the greatest mortality risk (adjusted hazard ratio = 2.34, 95% confidence interval: 1.24, 4.43).

Does deployment to Iraq and Afghanistan affect respiratory health of US military personnel?

OBJECTIVE: To evaluate the association between postdeployment respiratory conditions and deployment to Iraq or Afghanistan. METHODS: We linked deployment history of US military personnel with postdeployment medical records. We then conducted a nested case-control study. RESULTS: Relative to a single deployment, multiple deployments were not significantly associated with obstructive pulmonary disease (odds ratio, 1.08; 95% confidence interval, 0.82 to 1.42). Cumulative time deployed was also not significantly associated with obstructive pulmonary disease. Nevertheless, we did note that the rate of respiratory symptoms and encounters for obstructive pulmonary diseases (predominantly asthma and bronchitis) increased from before to after deployment. CONCLUSIONS: In a population of active duty US military personnel, we observed an increase in postdeployment respiratory symptoms and medical encounters for obstructive pulmonary diseases, relative to predeployment rates, in the absence of an association with cumulative deployment duration or total number of deployments.

Respiratory health status of US Army personnel potentially exposed to smoke from 2003 Al-Mishraq Sulfur Plant fire.

OBJECTIVE: To assess the impact of exposure to a 2003 sulfur plant fire on the health of deployed US Army personnel. METHODS: The authors identified a small firefighter group known to be at the fire source and a larger, more dispersed population. Self-reported health status and respiratory health outcomes for these two groups were reviewed compared with two unexposed groups. RESULTS: Self-reported health concerns, difficulty breathing, and shortness of breath were common in the exposed. Rates for chronic respiratory conditions increased in all groups from before to after deployment. Postdeployment medical encounters for chronic respiratory conditions among the exposed did not differ significantly from the unexposed comparison groups. CONCLUSION: Potential exposure to the sulfur fire was positively associated with self-reported health concerns and symptoms but not with clinical encounters for chronic respiratory health conditions.

The use of electronic pharmacy data to investigate prescribed medications and fatal motor vehicle crashes in a military population, 2002-2006.

The authors examined the association between prescribed medications and fatal motor vehicle crashes (MVCs) in an active duty military population between 2002 and 2006. Using a case-control design, MVC deaths were ascertained using a military mortality registry, and an integrated health system database provided information on health system eligibility, pharmacy transactions, and medical encounters. Cases and controls were matched on comparable observation time outside periods of deployment. Among selected categories, only one, antidepressant medications, was an independent predictor of fatal MVC (odds ratio, 3.19; 95% confidence interval, 1.01-10.07). Male gender, Black race, enlisted rank, service branch (Navy and Marine Corps), and selected co-morbidities were also independent predictors. Unexpectedly, the odds of younger age quartiles (< 27 years) and history of deployment were reduced for MVC cases. Although results need to be considered in the context of data limitations, the association between prescribed antidepressants and fatal MVC may reflect unmeasured co-morbidities, such as combined effects of prescribed and over-the-counter medications and/or alcohol or other substance abuse. Younger individuals, representing new military accessions in training or returning from deployment with serious injuries, may have fewer opportunities to operate vehicles, or targeted efforts to reduce MVC following deployment may be showing a positive effect.

The Joint Medical Workstation (JMeWS) database in 2003: intradeployment health encounters of military personnel supporting Operations Enduring Freedom and Iraqi Freedom.

The Joint Medical Work Station (JMeWS) is a theater medical surveillance system that integrates information from three separate health data collection systems for the Army, Navy, Air Force, and Marines. Our objective was to characterize JMeWS data during its first year of implementation in 2003. We conducted a descriptive analysis of health events documented in JMeWS among military personnel deployed to Operations Enduring Freedom and Iraqi Freedom. Among the 38,498 individuals (7.8%) with a JMeWS record, women, college-educated, older individuals, and Reserve/Guard personnel were over-represented. There was wide variability by service (Air Force, 25%; Army, 5.5%; Marine Corps, 1.2%; and Navy, 0.6%). The most common diagnoses were in the categories of injury and poisoning, respiratory conditions, and musculoskeletal disorders. Differences in distribution of the various patient encounter modules in theater likely resulted in variable data capture across services. System enhancements should improve future applications.

The long-term hospitalization experience following military service in the 1991 Gulf War among veterans remaining on active duty, 1994-2004.

BACKGROUND: Despite more than a decade of extensive, international efforts to characterize and understand the increased symptom and illness-reporting among veterans of the 1991 Gulf War, concern over possible long-term health effects related to this deployment continue. The purpose of this study was to describe the long-term hospitalization experience of the subset of U.S. Gulf War veterans still on active duty between 1994 and 2004. METHODS: Gulf War veterans on active duty rosters as of October 1, 1994, were identified (n = 211 642) and compared with veterans who had separated from military service and then assessed for attrition at three-year intervals during a 10-year follow-up period, examining demographic and military service characteristics, Gulf War exposure variables, and hospitalization data. Cox proportional hazard modeling was used to evaluate independent predictors of all-cause hospitalization among those still on active duty and to estimate cumulative probability of hospitalization, 1994-2004, by service branch. RESULTS: Members of our 1994 active duty cohort were more likely to be officers, somewhat older, and married compared with those who had separated from the military after serving in the 1991 Gulf War. Selected war-related exposures or experiences did not appear to influence separation with the exception of in-theater presence during the brief ground combat phase. Overall the top three diagnostic categories for hospitalizations were musculo-skeletal, injury and poisoning, and digestive disorders. Diseases of the circulatory system and symptoms, signs, and ill-defined conditions increased proportionately over time. In-theater hospitalization was the only significant independent predictor of long-term hospitalization risk among selected war-related exposures or experiences examined. The cumulative probability of hospitalization was highest for Army and lowest for Marines. CONCLUSION: Our results were generally consistent with a previous hospitalization study of US Gulf War veterans for the period August 1991 to July 1999. Although lack of a comparison group for our study limits interpretation of overall findings, intra-cohort analyses showed no significant associations between long-term hospitalization and war-related exposures or experiences, with the exception of in-theater hospitalization, within our active duty subset of 1991 Gulf War veterans.

Fatal motor vehicle crashes among veterans of the 1991 Gulf War and exposure to munitions demolitions at Khamisiyah: a nested case-control study.

BACKGROUND: A proposed explanation for the observed higher risk of fatal motor vehicle crashes (MVC) among 1991 Gulf War-deployed veterans is neurocognitive deficits resulting from nerve agent exposure at Khamisiyah, Iraq. Our objective was to assess any association between postwar fatal MVC and possible nerve agent exposure based on 2000 modeled plume data. METHODS: Cases were defined as MVC deaths with a record in the Department of Transportation Fatality Analysis Reporting System through 1995. Cases (n = 282) and controls (n = 3,131) were derived from a larger nested case-control study of Gulf War-era veterans and limited to Army, male, deployed personnel. Exposure and cumulative dose by case-control status were analyzed using multivariate techniques. RESULTS: Exposure status was not associated with fatal MVC (OR 0.96, 95% CI 0.72-1.26), nor were tertiles of cumulative dose. CONCLUSIONS: Findings do not support an association between possible exposures at Khamisiyah and postwar fatal MVC among Gulf War veterans.

Motor vehicle fatalities among Gulf War era veterans: characteristics, mechanisms, and circumstances.

OBJECTIVES: Our objective was to describe fatal motor vehicle crashes (MVC) among veterans of the 1991 Gulf War era and to compare the distribution of crash and individual characteristics between those deployed to the Gulf War (GWV) and those not deployed (NDV). METHODS: We compared individual characteristics, crash mechanisms, and crash circumstances between 765 GWV and 553 NDV who died from MVC within the first five years of the war, between May 1991 and December 1995. RESULTS: Overall, GWV and NDV who died from a MVC were more likely to be enlisted males (97%), 21-30 years old (72%), have a high school education or less (91%), drive a passenger car (52%), and not use restraints (60%). The overall annual rate of motor vehicle fatalities for GWV (23.6 per 100,000; 95% confidence interval: 21.9-25.3) was significantly greater than the rate for NDV (15.9, 95% CI: 14.6-17.3). GWV with the highest motor vehicle fatality rates include males (24.8, 95% CI: 23.0-26.6), 17-20 year olds (105.0, 95% CI: 78.2-138.1), and those not married (27.3, 95% CI: 25.1-30.1). Adjusting for differences in age distribution across GWV and NDV did not account for the difference in rates. Characteristics of MVC fatalities that were over-represented among GWV include serving as regular active duty (p = 0.001), having a high school education or less (p = 0.01), being involved in a single-vehicle crash (p = 0.008), and dying within the first hour following the crash (p = 0.004). Also, we identified a greater proportion of alcohol-related crashes among GWV during the late night and early morning hours. CONCLUSIONS: The highest rates of motor vehicle fatality among young, single males in the military mirror the experience of the general population. Further research is necessary to determine modifiable risk factors that can be targeted for specific interventions and whether the elevated late night alcohol-related crash rate among GWV is an effect of deployment or an inherent population bias among those selected for operational deployments.

Understanding the effect of deployment on the risk of fatal motor vehicle crashes: a nested case-control study of fatalities in Gulf War era veterans, 1991-1995.

Motor vehicle crashes (MVCs) are an important cause of morbidity and premature loss of life among military personnel during peacetime and particularly following combat. A nested case-control study of fatal MVC occurring between 1991 and 1995 was conducted in a cohort of Gulf War era veterans. Cases were validated MVC deaths in the Fatality Analysis Reporting System. Controls were selected using risk set sampling by gender and year of case ascertainment in a 10:1 ratio. Preliminary results, consistent with previous reports of increased fatal MVC risk among returning combat veterans, showed a crude odds ratio of 1.45 (95% confidence interval 1.27-1.65). Multivariable logistic regression modeling was used to identify important independent predictors, as well as to quantify the influence of deployment on a risk profile for fatal MVC. Because of significant interaction between deployment and inpatient diagnosis of substance abuse, the final model was stratified by deployment status. Results suggest that demographic, military, and behavioral characteristics of deployed healthy warriors are similar to the risk profile for fatal MVC. In addition to young, single, high school-educated, enlisted male personnel, those who served during times of ground combat, particularly in infantry, gun crews, or seamanship occupations, should be targeted for preventive interventions.

Leveraging existing databases to study vehicle crashes in a combat occupational cohort: epidemiologic methods.

BACKGROUND: The US military is a large, well-defined occupational cohort offering tremendous opportunities to study risk factors for important health outcomes. This article describes our nested case-control methods to evaluate risk factors for fatal motor vehicle crashes (MVC) within all Service branches in a 1991 Gulf War era cohort. METHODS: We identified 1,343 cases of fatal MVC between 1991 and 1995 that were also included in the Department of Transportation's Fatality Analysis Reporting System database and, using risk set sampling, selected 13,430 controls. Our final analytic dataset consisted of 980 male driver cases and 12,807 controls linked to multiple databases. RESULTS: Cases were disproportionately younger, less educated, not married, enlisted, and deployed to the Gulf War, compared to controls. CONCLUSIONS: The ability to leverage multiple databases to study risk factors for fatal MVC is clearly advantageous and could eventually lead to the reduction of fatalities in similar occupational cohorts.

A case-control study of asthma among U.S. Army Gulf War veterans and modeled exposure to oil well fire smoke.

OBJECTIVE: Thousands of American troops were exposed to oil well fire smoke during the Persian Gulf War, but the actual impact of this on their health is unknown. To assess the potential association between physician-diagnosed asthma and objective estimates of oil fire smoke, we conducted a case-control study of Army Gulf War veterans. METHODS: Subjects were participants in the Comprehensive Clinical Evaluation Program. Cases had physician-diagnosed asthma; controls were selected from the population of noncases. The two estimates of exposure were cumulative exposure and number of days at high levels. RESULTS: A total of 873 cases and 2,464 controls were included. Significant associations were observed between asthma and both estimates of exposure, with an adjusted odds ratio of 1.4 (95% confidence interval = 1.11.8) for both the highest levels of cumulative exposure and days exposed to high levels. A dose response was observed for both exposure measures. CONCLUSIONS: We found significant associations between asthma and oil fire smoke exposure. Because much of the medical history was not available, an etiological association cannot be determined from this study, and additional research is needed.