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Objectives Regular vigorous physical activity (PA) and high levels of physical fitness (PF) confer health benefits. Conversely, sedentary time is a risk factor for chronic illness, independent of PA. We evaluated associations between self-reported PA, sedentary time, and objective PF measures in military Service members. Design Cross-sectional study including 10,105 Air Force Millennium Cohort participants with a valid physical fitness assessment (PFA). Methods Linear regression assessed associations between self-report PA, screen time, and usual activity and abdominal circumference (AC) and VO2 max; logistic regression was used for PFA failure. We stratified by age and sex. Results Men who self-reported high versus low levels of PA had greater AC (19–29 years: β = 0.23 in., 95% CI 0.07, 0.39; 30–39 years: β = 0.45 in., 95% CI 0.17, 0.72). High versus low self-reported PA was also associated with greater VO2Max (β =: 0.81–1.41 mL/kg/min). Self-reported strength training for ≥2 days/week was associated with greater VO2Max in 19–29 year old men (β = 0.84 mL/kg/min, 95% CI 0.09, 0.60) and 30–39 year old women (β = 0.74 mL/kg/min, 95% CI 0.02, 1.46). For younger men and women, Conclusions Self-reported PA and screen time were associated with some objective PF measures, including VO2Max and AC. However, screen time alone was associated with PFA failure.

Smoking rates among U.S. Service members and veterans have been consistently higher than in civilian populations. While much has been published about tobacco use in both military and veteran populations, smoking patterns during transition from military to veteran status remains unclear. We studied military members participating in the Millennium Cohort Study, who separated from their respective Services between baseline and first follow-up survey ( N = 5,510). Two generalized estimating equation models were used to examine any association between smoking status and time to military separation (days between baseline survey and separation), as well as smoking during transition and reason for separation. Reason for separation was categorized into three groups: (1) not meeting military standards or judicial-related reasons, (2) drugs-/alcohol-related misconduct, and (3) other types of separation including retirement, pregnancy, and so on. Statistical models accounted for baseline smoking and demographic/military/health behavioral/mental health characteristics. Overall, we observed a decline in smoking prevalence over time (19.5%, 16.7%, 15.2%, and 12.6%, respectively). However, we found a 22% increase in the odds of smoking among those who stayed in the military between 3 months and 1 year, compared to those who stayed 2+ years. Additionally, participants separating for standard/judicial reason(s) showed 69% increased smoking compared to those with other reasons for separation. The time period immediately prior to Service separation and certain types of separation were associated with increased odds of smoking. Thus, smoking cessation interventions should target Service members during this transition period to potentially reduce smoking prevalence after separation.

Study Design. A prospective cohort study. Objective. Activities performed during military operations vary in complexity and physical demand. The risk for mental illness following military combat deployment has been well documented. However, information regarding the possible contribution of back pain to decreased mental and functional health is scarce. To our knowledge, this is the first study to prospectively assess deployment and self-reported recent back pain in a population-based U.S. military cohort. Summary of Background Data. The study consisted of Millennium Cohort participants who were followed for the development of back pain for an average of 3.9 years. Methods. Descriptive statistics and longitudinal analyses were used to assess the temporal relationship of deployment with self-reported recent back pain at follow-up (N = 53,933). Results. Recent back pain was self-reported by 8379 (15.5%) participants at follow-up. After adjusting for covariates, deployers with combat experiences had higher odds [odds ratio (OR) = 1.38, 95% confidence interval (95% CI): 1.28–1.50] of recent back pain than noncombat deployers. There was no association between recent back pain and nondeployers compared with noncombat deployers. Service support/supply handlers were at an increased odds of reporting recent back pain (OR = 1.11, 95% CI: 1.02–1.21) than functional support/administration occupations. Occupations associated with a physically demanding work environment had a higher risk of back pain. Conclusion. Deployers with combat experiences were more likely to report back pain postdeployment. This well-defined group of military personnel may potentially benefit from integrated prevention efforts. Level of Evidence: 3

OBJECTIVES: Functional gastrointestinal disorders occur more frequently among deployed veterans, although studies evaluating the relative impact of risk factors, including stress and antecedent infectious gastroenteritis (IGE), are limited. We examined risk factors for new-onset irritable bowel syndrome (IBS) among active duty participants in the military's Millennium Cohort Study. METHODS: Medical encounter data from 2001 to 2009, limited to Cohort members on active duty, were used to identify incident IBS cases (any and highly probable). IGE was identified using medical encounter or self-report. Covariate data were obtained from the Millennium Cohort Study surveys and analyzed using Cox proportional hazards methods. RESULTS: Overall, 41,175 Cohort members met the eligibility criteria for inclusion and 314 new-onset cases of IBS were identified among these. Significant risk factors (adjusted hazard ratio, 95% confidence interval) included antecedent IGE (2.05, 1.53–2.75), female gender (1.96, 1.53–2.52), number of life stressors (1: 1.82, 1.37–2.41; 2: 2.86, 2.01–4.06; 3+: 6.69, 4.59–9.77), and anxiety syndrome (1.74, 1.17–2.58). Limited to highly probable IBS, a stronger association with antecedent IGE was observed, particularly when based on medical encounter records (any IGE: 2.20, 1.10–4.43; medical encounter IGE only: 2.84, 1.33–6.09). Precedent anxiety or depression and IGE interacted with increased IBS risk compared with IGE alone. CONCLUSIONS: These results confirm previous studies on the association between sociodemographic or life stressors and IBS. IGE was significantly associated with IBS risk. Whether deployed or not, US service members often encounter repeated exposure to high levels of stress, which, combined with other environmental factors such as IGE, may result in long-term debilitating functional gastrointestinal disorders.

The objective of this study was to define the risk of hearing loss among US military members in relation to their deployment experiences. Data were drawn from the Millennium Cohort Study. Self-reported data and objective military service data were used to assess exposures and outcomes. Among all 48,540 participants, 7.5% self-reported new-onset hearing loss. Self-reported hearing loss showed moderate to substantial agreement (k = 0.57-0.69) with objective audiometric measures. New-onset hearing loss was associated with combat deployment (adjusted odds ratio [AOR] = 1.63, 95% confidence interval [CI] = 1.49-1.77), as well as male sex and older age. Among deployers, new-onset hearing loss was also associated with proximity to improvised explosive devices (AOR = 2.10, 95% CI = 1.62-2.73) and with experiencing a combat-related head injury (AOR = 6.88, 95% CI = 3.77-12.54). These findings have implications for health care and disability planning, as well as for prevention programs.

Maternal depression is a common condition among new mothers that can be associated with poor maternal health and negative consequences on infant health. Little research has been conducted to examine maternal depression, especially among military mothers, where unique conditions often exist. Using data from a large military cohort, this study prospectively examined the relationship between deployment experience before and after childbirth and maternal depression among U.S. service women.The study included 1,660 female Millennium Cohort participants who gave birth during active duty service and completed baseline and follow-up questionnaires between 2001 and 2008. Maternal depression was assessed at follow-up using Primary Care Evaluation of Mental Disorders Patient Health Questionnaire criteria.Deployment before childbirth, regardless of combat experience, and deployment without combat experience after childbirth did not increase the risk of maternal depression. Women who deployed and reported combat experience after childbirth were at increased risk for maternal depression compared with nondeployed women who gave birth (adjusted odds ratio [OR] 2.01, 95% confidence interval [CI] 1.17-3.43). Among the subgroup of female combat deployers, however, women who gave birth did not have a significantly increased risk for depression compared with those who did not give birth.Military women who deployed with combatlike experiences after childbirth were at increased risk for postdeployment maternal depression. The risk, however, appeared primarily related to combat rather than childbirth-related experiences.

Previous research has shown that military women often experience potentially severe health outcomes following deployment. Data from the Millennium Cohort Study, a 21-year longitudinal study examining the health effects of military service, were used to examine this issue. In longitudinal analyses (2001-2008) carried out among US military women (n = 17,481), the authors examined positive screens for depression, anxiety, panic, and posttraumatic stress disorder in relation to deployment in support of the operations in Iraq and Afghanistan, while adjusting for relevant baseline and time-varying covariates. Women who were deployed and reported combat-related exposures had greater odds than nondeployed women of reporting symptoms of a mental health condition (odds ratio = 1.91, 95% confidence interval: 1.65, 2.20), after adjustment for demographic, military, and behavioral covariates. In addition, higher stress, problem drinking, and a history of mental illness were significantly associated with increased risk of later mental health conditions. In contrast, women in the Reserves or National Guard and those with higher education were at decreased risk of mental health conditions (all P 's < 0.01). As the roles and responsibilities of women in the military expand and deployments continue, designing better prevention and recovery strategies specifically for women are critical for overall force health protection and readiness.

In the United Kingdom and United States, these two independent cohort studies have been instituted to prospectively study the health of service personnel and veterans. From comparisons with baseline information, these studies are designed to better inform the military and the public on how best to protect the health of their armed forces and better understand the long-term risks of some occupational exposures that extend beyond military communities. In order to do this, these studies consider: 1) The underlying physical and mental health of the military populations before, during, and after military service; and 2) The specific effects of deployment, deployment-related exposures, and other occupational exposures upon personnel compared with unexposed subgroups. Whilst previous studies have attempted to address these topics, they have often been limited in their generalisability to all service branches and components of the military, or previous population-based methodologies have been largely limited to cross-sectional or retrospective methods. Although follow-up to the National Vietnam Veterans Readjustment Survey, called the National Vietnam Veterans Longitudinal Study, is still ongoing, this study is focused on a single deployment. Similarly, the Air Force Health study, a 20-year longitudinal study of approximately 20,000 Vietnam veterans, assessed potential health effects associated with exposure to aerial spraying of dioxins. Here, we present two prospective, longitudinal, multi-service studies of active duty and Reserve/National Guard personnel that will continue to follow participants even after they have left military service. We describe these two studies in detail, comparing study populations, methodology, and the published literature so far. Potential areas for future collaboration are also explored. By understanding the inherent similarities and differences between these two cohorts and leveraging each study?s unique strengths and strategies to minimize

ACCORDING TO A 2008 REPORT FROM THE NATIONAL SLEEP FOUNDATION, AMERICANS ARE WORKING MORE AND SLEEPING LESS, WITH THE AVERAGE work day lasting 9 hours 28 minutes and time in bed only 6 hours 55 minutes.1 The US military is at particularly high risk for sleep disturbances due to hazardous working conditions, inconsistent work hours, harsh environments, routine exposure to loud noises, and crowded sleeping spaces.2,3 Exposures to these adverse working conditions are often intensified during deployments, including the current increased operational tempo, with lengthy and frequent deployments, as well as demanding training exercises. Deployment-related factors may lead to sleep complaints, including circadian desynchronosis, total or partial sleep deprivation, lengthy sleep latency, and wakening after sleep onset that may, in turn, exacerbate mental and physical health symptoms following deployment.2,3 The quantity and quality of sleep affect many aspects of physical and mental health.4–12 Military personnel deployed in support of Operation Iraqi Freedom and Operation Enduring Freedom may be at increased risk for chronic sleep loss, as well as many other adverse physical and mental conditions, compared with nondeployed military personnel.13–15 Sleep deprivation has been studied extensively and is associated with many physical and psychological effects, including increased risk-taking behavior,7,11 decreased threat detection,10 impaired decision making,7,11,12 performance degradation,4,8,9 mood disturbances,8 and tunnel vision.6 Short sleep duration has also been associated with obesity, weight gain, and heart disease.5,16,17 A recent cross-sectional study of 156 deployed US Air Force Airmen found that 40% of respondents suffered from at least 1 sleep disturbance, and 75% of respondents reported diminished sleep quality while deployed when compared to sleep quality at home.3 The purpose of this study was to determine any association between deployment in support of the operations in Iraq and Afghanistan and sleep quantity and quality in a large military population. We hypothesized that military personnel who had deployed would have more trouble sleeping and sleep less than those who have not deployed. The Millennium Cohort Study18 includes all Service branches of the US military, active-duty, Reserve, and National Guard personnel. A substantial proportion (22%) of cohort members were deployed in support of the operations in Iraq and Afghanistan between baseline and follow-up surveys. This population provided valuable information on sleep patterns, as well as behavioral, occupational, and demographic characteristics among participants who completed their survey during and after deployment.

OBJECTIVE Few prospective data exist on the risk of diabetes in individuals serving in the U.S. military. The objectives of this study were to determine whether military deployment, combat exposures, and mental health conditions were related to the risk of newly reported diabetes over 3 years. RESEARCH DESIGN AND METHODS Data were from Millennium Cohort Study participants who completed baseline (July 2001–June 2003) and follow-up (June 2004–February 2006) questionnaires (follow-up response rate = 71.4%). After exclusion criteria were applied, adjusted analyses included 44,754 participants (median age 36 years, range 18–68 years). Survey instruments collected demographics, height, weight, lifestyle, military service, clinician-diagnosed diabetes, and other physical and mental health conditions. Deployment was defined by U.S. Department of Defense databases, and combat exposure was assessed by self-report at follow-up. Odds of newly reported diabetes were estimated using logistic regression analysis. RESULTS Occurrence of diabetes during follow-up was 3 per 1,000 person-years. Individuals reporting diabetes at follow-up were significantly older, had greater baseline BMI, and were less likely to be Caucasian. After adjustment for age, sex, BMI, education, race/ethnicity, military service characteristics, and mental health conditions, only baseline posttraumatic stress disorder (PTSD) was significantly associated with risk of diabetes (odds ratio 2.07 [95% CI 1.31–3.29]). Deployments since September 2001 were not significantly related to higher diabetes risk, with or without combat exposure. CONCLUSIONS In this military cohort, PTSD symptoms at baseline but not other mental health symptoms or military deployment experience were significantly associated with future risk of self-reported diabetes.

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 (

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.

Objective In response to health concerns of military members about deployment and other service-related exposures, the Department of Defense (DoD) initiated the largest prospective study ever undertaken in the U.S. military. Study Design and Setting The Millennium Cohort uses a phased enrollment strategy to eventually include more than 100,000 U.S. service members who will be followed up through the year 2022, even after leaving military service. Subjects will be linked to DoD and Veterans Affairs databases and surveyed every 3 years to obtain objective and self-reported data on exposures and health outcomes. Results The first enrollment phase was completed in July 2003 and resulted in 77,047 consenting participants, well representative of both active-duty and Reserve/Guard forces. This report documents the baseline characteristics of these Cohort members, describes traditional, postal, and Web-based enrollment methods; and describes the unique challenges of enrolling, retaining, and following such a large Cohort. Conclusion The Millennium Cohort was successfully launched and is becoming especially relevant, given current deployment and exposure concerns. The Cohort is representative of the U.S. military and promises to provide new insight into the long-term effects of military occupations on health for years to come.

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.

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).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.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.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.

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.

Attrition among medical students is a concern for the institution, the individual, and the profession. Disenrollment has an impact on the institution, in terms of academic reputation and resources expended, and the individual, in terms of self-esteem, personal finances, and opportunity costs. This study summarizes the results of an epidemiologic study of student attrition conducted at the only federal medical school in the United States--the Uniformed Services University of the Health Sciences in Bethesda, Maryland--and describes the association between demographic and selected quantitative variables for those students who graduated or remained enrolled and those who disenrolled. Both sex (female) and a decelerated curriculum were predictive of attrition in this medical student population. The records of the students who left Uniformed Services University of the Health Sciences without graduating were examined to ascertain the presence of noncognitive issues surrounding disenrollment; over one-half of the students who disenrolled left voluntarily and for nonacademic reasons.

There has been much concern among the public and veterans that specific environmental exposures incurred during the Gulf War were the cause of subsequent illness among Gulf War veterans. In this historical cohort study, the authors compared the postwar morbidity of US military personnel exposed to smoke from the 1991 Kuwaiti oil well fires with that of unexposed personnel. Complete exposure and demographic data were available for 405,142 active-duty Gulf War veterans who did not remain in the region after the war. The authors used data from all Department of Defense hospitals for the period August 1, 1991-July 31, 1999 to estimate rates of hospitalization due to any cause, hospitalization due to a diagnosis in one of 15 major categories, and hospitalization due to one of nine diagnoses likely to be manifestations of smoke exposure. Exposures to particulate matter from oil-well-fire smoke were based on the integration of meteorologic data, diffusion modeling, and troop location data. The authors constructed seven exposure groups combining duration and amount of exposure. In Cox modeling, three of the 25 models showed an increased adjusted risk of hospitalization. However, there was no evidence of a dose-response relation. Despite some limitations, these data do not support the hypothesis that Gulf War veterans have an increased risk of postwar morbidity from exposure to Kuwaiti oil-well-fire smoke.

Symptoms and illnesses reported by veterans of the 1991 Gulf War era are a cause of potential concern for those military members who have deployed to the Gulf region in support of more recent contingency operations in Iraq and Afghanistan. In the present study, we quantified self-reported symptoms from participants in the Millennium Cohort Study, a prospective study representing all US service branches, including both active duty and Reserve/National Guard components (2001-2008). Self-reported symptoms were uniquely compared with those in a cohort of subjects from the 1991 Gulf War to gain context for the present report. Symptoms were then aggregated to identify cases of chronic multisymptom illness (CMI) based on the case definition from the Centers for Disease Control and Prevention. The prevalence of self-reported CMI symptoms was compared with that collected in 1997-1999 from a study population of US Seabees from the 1991 Gulf War, as well as from deployed and nondeployed subgroups. Although overall symptom reporting was much less in the Millennium Cohort than in the 1991 Gulf War cohort, a higher prevalence of reported CMI was noted among deployed compared with nondeployed contemporary cohort members. An increased understanding of coping skills and resilience and development of well-designed screening instruments, along with appropriate clinical and psychological follow-up for returning veterans, might help to focus resources on early identification of potential long-term chronic disease manifestations.

Potential adverse mental health effects of deployment, including depression, are an ongoing concern. Although a previous study assessed under-reporting of depression on post-deployment health assessments compared to anonymous surveys, those results were not examined at the individual level to identify demographic or military factors that may be associated with unwillingness to report depression symptoms.To compare self-reported depression symptoms on post-deployment health assessments with responses to the same depression questions on a research survey.This cross-sectional study analyzed depression screening responses from 2001 to 2008 from participants of the Millennium Cohort Study, a longitudinal military cohort study, who completed a post-deployment health assessment within 30 days of a research survey. Kappa statistics and percent positive and negative agreement were calculated. Demographic and military characteristics associated with discordant screening results were examined. Initial analyses were performed in 2011, with additional analyses in 2013.Moderate agreement (κ=0.464) was observed between paired survey responses. A higher proportion of active duty members, the unmarried, and new accessions into military service endorsed depression symptoms on the research survey but not the military-linked survey. In stratified analyses, agreement was higher in Reserve/National Guard members than active duty (κ=0.561 vs 0.409). New active duty accessions showed lower agreement (κ=0.388), as did unmarried active duty participants (κ=0.304).Deployment health surveys are important tools for identifying returning service members experiencing depression symptoms. However, these findings suggest that ongoing stigma and barriers to appropriate follow-up mental health care remain to be addressed in the military setting.

Beginning in 2005, the incidence of suicide deaths in the US military began to sharply increase. Unique stressors, such as combat deployments, have been assumed to underlie the increasing incidence. Previous military suicide studies, however, have relied on case series and cross-sectional investigations and have not linked data during service with postservice periods.To prospectively identify and quantify risk factors associated with suicide in current and former US military personnel including demographic, military, mental health, behavioral, and deployment characteristics.Prospective longitudinal study with accrual and assessment of participants in 2001, 2004, and 2007. Questionnaire data were linked with the National Death Index and the Department of Defense Medical Mortality Registry through December 31, 2008. Participants were current and former US military personnel from all service branches, including active and Reserve/National Guard, who were included in the Millennium Cohort Study (N = 151,560).Death by suicide captured by the National Death Index and the Department of Defense Medical Mortality Registry.Through the end of 2008, findings were 83 suicides in 707,493 person-years of follow-up (11.73/100,000 person-years [95% CI, 9.21-14.26]). In Cox models adjusted for age and sex, factors significantly associated with increased risk of suicide included male sex, depression, manic-depressive disorder, heavy or binge drinking, and alcohol-related problems. None of the deployment-related factors (combat experience, cumulative days deployed, or number of deployments) were associated with increased suicide risk in any of the models. In multivariable Cox models, individuals with increased risk for suicide were men (hazard ratio [HR], 2.14; 95% CI, 1.17-3.92; P = .01; attributable risk [AR], 3.5 cases/10,000 persons), and those with depression (HR, 1.96; 95% CI, 1.05-3.64; P = .03; AR, 6.9/10,000 persons), manic-depressive disorder (HR, 4.35; 95% CI, 1.56-12.09; P = .005; AR, 35.6/10,000 persons), or alcohol-related problems (HR, 2.56; 95% CI, 1.56-4.18; P.001; AR, 7.7/10,000 persons). A nested, matched case-control analysis using 20:1 control participants per case confirmed these findings.In this sample of current and former military personnel observed July 1, 2001-December 31, 2008, suicide risk was independently associated with male sex and mental disorders but not with military-specific variables. These findings may inform approaches to mitigating suicide risk in this population.

OBJECTIVE Research has suggested that a higher risk of type 2 diabetes associated with sleep characteristics exists. However, studies have not thoroughly assessed the potential confounding effects of mental health conditions associated with alterations in sleep. RESEARCH DESIGN AND METHODS We prospectively assessed the association between sleep characteristics and self-reported incident diabetes among Millennium Cohort Study participants prospectively followed over a 6-year time period. Surveys are administered approximately every 3 years and collect self-reported data on demographics, height, weight, lifestyle, features of military service, sleep, clinician-diagnosed diabetes, and mental health conditions assessed by the PRIME-MD Patient Health Questionnaire and the PTSD Checklist–Civilian Version. Statistical methods for longitudinal data were used for data analysis. RESULTS We studied 47,093 participants (mean 34.9 years of age; mean BMI 26.0 kg/m2; 25.6% female). During 6 years of follow-up, 871 incident diabetes cases occurred (annual incidence 3.6/1,000 person-years). In univariate analyses, incident diabetes was significantly more likely among participants with self-reported trouble sleeping, sleep duration

To investigate the relationship between chronic multisymptom illness (CMI) and possible exposure to an open-air burn pit at three selected bases among those deployed to operations in Iraq and Afghanistan.Chronic multisymptom illness (reporting at least one symptom in at least two of the following symptom constructs: general fatigue; mood and cognition problems; and musculoskeletal discomfort) was assessed, differentiating by potential burn pit exposure, among deployers who completed 2004 and 2007 Millennium Cohort questionnaires.More than 21,000 Cohort participants were deployed in support of the current operations, including more than 3000 participants with at least one deployment within a 3-mile radius of a documented burn pit. After adjusting for covariates, no elevated risk of CMI was observed among those exposed.There was no increase in CMI symptom reporting in those deployed to three selected bases with documented burn pits compared with other deployers.

Background. After September 11, 2001, the United States entered into extended operations in Iraq and Afghanistan. Individuals joining the military in the post-September 11 era committed to potential prolonged and repeated deployments. It has been hypothesized that those who entered military service in the pre-September 11 era might have expectations incongruent with their subsequent experiences, and this may increase their risk for mental disorders. Methods. A subset of Millennium Cohort members who joined the military during 1995-1999 were compared with a subset of Millennium Cohort members who joined the military in 2002 or later. Outcomes included new-onset posttraumatic stress disorder (PTSD), depression, panic/anxiety disorders, and alcohol-related problems. Multivariable methods were adjusted for differences in demographic and military characteristics. Findings. Those who entered service in the pre-September 11 era had slightly lower odds of new-onset PTSD (odds ratio 0.74, 95% confidence interval 0.59-0.93) compared with the post-September 11 cohort. There were no statistically significant differences in rates of new-onset depression, panic/anxiety disorders, or alcohol-related problems between the groups. Interpretation. The cohort who entered military service in the pre-September 11 era did not experience higher rates of newonset mental disorders when compared with the cohort who entered service after September 11, 2001.

Characterize migraine and other headache disorders within a large population-based US military cohort, with an emphasis on the temporal association between military deployment and exposure to combat.Little research has been published on the prevalence of headache disorders in the US military population, especially in relation to overseas deployments and exposure to combat. A higher than expected prevalence of migraine has previously been reported among deployed US soldiers in Iraq, suggesting an association. Headache disorders, including migraine, could have important effects on the performance of service members.A total of 77,047 US active-duty, Reserve, and National Guard members completed a baseline questionnaire between July 2001 to June 2003 for the Millennium Cohort Study. Headache disorders were assessed using the following survey-based measures: self-reported history of provider-diagnosed migraine, recurrent severe headache within the past year, and recent headaches/bothered a lot within the past 4 weeks. Follow-up surveys were completed on average 3 years after baseline (mean=2.7 years; range=11.4 months to 4.5 years).The overall male and female prevalence of self-reported headache conditions at baseline were: provider-diagnosed migraine, 6.9% and 20.9%, respectively; recurrent severe headache, 9.4% and 22.3%, respectively; and bothered a lot by headaches, 3.4% and 10.4%, respectively. Combat deployers had significantly higher odds of any new-onset headache disorders than non-deployers (adjusted odds ratios=1.72 for men, 1.84 for women; 95% confidence intervals, 1.55-1.90 for men, 1.55-2.18 for women), while deployers without combat exposure did not.Deployed personnel with reported combat exposure appear to represent a higher risk group for new-onset headache disorders. The identification of populations at higher risk of development of headache provides support for targeted interventions.

Physical injury has been associated with the development of posttraumatic stress disorder (PTSD). Previous studies have retrospectively examined the relationship of preinjury psychiatric status and postinjury PTSD with conflicting results, but no prospective studies regarding this subject have been conducted, to our knowledge.To prospectively assess the relationship of predeployment psychiatric status and injury severity with postdeployment PTSD.Prospective, longitudinal study.United States military personnel deployed in support of the conflicts in Iraq and Afghanistan.United States service member participants in the Millennium Cohort Study who completed a baseline questionnaire (from July 1, 2001, through June 30, 2003) and at least 1 follow-up questionnaire (from June 1, 2004, through February 14, 2006, and from May 15, 2007, through December 31, 2008) and who were deployed in the intervening period. Self-reported health information was used to prospectively examine the relationship between baseline psychiatric status and follow-up PTSD in injured and uninjured deployed individuals.A positive screening result using the PTSD Checklist-Civilian Version.Of 22 630 eligible participants, 1840 (8.1%) screened positive for PTSD at follow-up, and 183 (0.8%) sustained a deployment-related physical injury that was documented in the Joint Theater Trauma Registry or the Navy-Marine Corps Combat Trauma Registry Expeditionary Medical Encounter Database. The odds of screening positive for PTSD symptoms were 2.52 (95% confidence interval, 2.01-3.16) times greater in those with 1 or more defined baseline mental health disorder and 16.1% (odds ratio, 1.16; 95% confidence interval, 1.01-1.34) greater for every 3-unit increase in the Injury Severity Score. Irrespective of injury severity, self-reported preinjury psychiatric status was significantly associated with PTSD at follow-up.Baseline psychiatric status and deployment-related physical injuries were associated with screening positive for postdeployment PTSD. More vulnerable members of the deployed population might be identified and benefit from interventions targeted to prevent or to ensure early identification and treatment of postdeployment PTSD.

Context High rates of alcohol misuse after deployment have been reported among personnel returning from past conflicts, yet investigations of alcohol misuse after return from the current wars in Iraq and Afghanistan are lacking. Objectives To determine whether deployment with combat exposures was associated with new-onset or continued alcohol consumption, binge drinking, and alcohol-related problems. Design, Setting, and Participants Data were from Millennium Cohort Study participants who completed both a baseline (July 2001 to June 2003; n=77 047) and follow-up (June 2004 to February 2006; n=55 021) questionnaire (follow-up response rate = 71.4%). After we applied exclusion criteria, our analyses included 48 481 participants (active duty, n = 26 613; Reserve or National Guard, n = 21 868). Of these, 5510 deployed with combat exposures, 5661 deployed without combat exposures, and 37 310 did not deploy. Main Outcome Measures New-onset and continued heavy weekly drinking, binge drinking, and alcohol-related problems at follow-up. Results Baseline prevalence of heavy weekly drinking, binge drinking, and alcohol-related problems among Reserve or National Guard personnel who deployed with combat exposures was 9.0%, 53.6%, and 15.2%, respectively; follow-up prevalence was 12.5%, 53.0%, and 11.9%, respectively; and new-onset rates were 8.8%, 25.6%, and 7.1%, respectively. Among active-duty personnel, new-onset rates were 6.0%, 26.6%, and 4.8%, respectively. Reserve and National Guard personnel who deployed and reported combat exposures were significantly more likely to experience new-onset heavy weekly drinking (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.36-1.96), binge drinking (OR, 1.46; 95% CI, 1.24-1.71), and alcohol-related problems (OR, 1.63; 95% CI, 1.33-2.01) compared with nondeployed personnel. The youngest members of the cohort were at highest risk for all alcohol-related outcomes. Conclusion Reserve and National Guard personnel and younger service members who deploy with reported combat exposures are at increased risk of new-onset heavy weekly drinking, binge drinking, and alcohol-related problems.

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.

To better understand the US military's global peacekeeping and combat operations, which may expose a growing population of American service women to challenging occupations and environments. Concordance between self-reported and electronic occupation codes for female participants in the Millennium Cohort was measured using kappa statistics. Multivariable logistic regression modeling was used to assess the odds of five self-reported potentially toxic environmental exposures or disturbing experiences among different occupational categories, while adjusting for demographic and military characteristics, including deployment. Self-reported occupations were moderately to highly reliable when compared with electronic occupation data. Active-duty and Reserve/Guard females differentially reported witnessing death or trauma and exposure to chemical or biological warfare, depleted uranium, or pesticides. Findings suggest that self-reported occupation can be used with a high degree of confidence. Occupational groups with higher odds of reporting military exposures of concern will be followed longitudinally through 2022 and prospectively compared using baseline and follow-up evaluations.

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. Language: en

To describe health patterns in evacuated military members during Operation Iraqi Freedom (OIF) and utilize demographic, diagnostic, and pre- and postdeployment health information to understand the utility of data collected for aeromedical evacuations.We conducted a descriptive analysis of U.S. evacuees from 2003 using data from the U.S. Transportation Command's Regulating and CommandControl Evacuation System and the Defense Medical Surveillance System.The typical patient was an Army male under the age of 29 requiring orthopedic or surgical care. Disease/nonbattle injuries were six times as common as battle injuries and 94% were classified as routine evacuees. Eighty-six percent had health data available in the Defense Medical Surveillance System. Two thirds had pre- and/or postdeployment questionnaire data.Combining data sources increases our understanding of disease patterns in deployed troops. Targeted preventive interventions can then be implemented. Changes in the U.S. Transportation Command's Regulating and CommandControl Evacuation System database can improve its utility as an epidemiological tool.

Objective. Investigation into the relationship between lifestyle factors (particularly cigarette smoking) and perceived oral health has been limited. Data from the third National Health and Nutrition Examination Survey (NHANES III), 1988–1994, were used to explore this relationship in a large sample of U.S. adults. Methods. This study used data on 13,357 dentate participants in NHANES III aged 20–79 years. In NHANES III, information on perceived dental health, sociodemographic attributes, smoking status, frequency of dental visits, dental insurance, and general health perception were collected during a home interview, and oral health status was assessed at a mobile examination center. Results. Overall, 34.4% of individuals in the study sample reported having an unfavorable perception of their dental health by qualifying it as “fair” or “poor.” Furthermore, 46.6% of smokers had an unfavorable dental health perception, compared to 28.3% of non-smokers. An interaction between smoking and race/ethnicity was found in logistic regression modeling. Stratified results show that cigarette smoking was not a significant predictor for an unfavorable dental health perception among individuals who self-identified as Mexican American, but smoking was a significant predictor for an unfavorable dental health perception among those who identified as non-Hispanic black or non-Hispanic white. Conclusions. This is the first study to describe the effects of smoking on dental health perception while controlling for examined oral health status. Because perceived dental health is a potential indicator for dental care utilization, a better knowledge of the factors that influence dental health perception is not only important for dental services planning, but also for understanding oral health–related quality of life issues. Additionally, given that smoking may negatively affect dental health perception, these findings have potential implications for smoking cessation activities conducted by dental care providers.

In response to concerns that Gulf War veterans were experiencing increased morbidity resulting from wartime exposures in the Gulf War, the Department of Veterans Affairs and the Department of Defense (DoD) initiated clinical registries to provide systematic health evaluations for self-referred Gulf War veterans. The authors used Cox's proportional hazard modeling with data from all DoD hospitals to estimate the probability of hospitalization resulting from any cause, resulting from diagnosis in a major diagnostic category, and resulting from a specific diagnosis of interest. After adjusting for other risk factors, registry participants were 1.43 times more likely to have a postwar hospitalization than registry nonparticipants (95% confidence interval, 1.40-1.46). These findings support the hypothesis that registry participants were more likely to experience postwar morbidity than veterans who chose not to enroll in the health registries.

The artificial environment encountered in submarine duty may affect the health of crewmembers. Previous studies of submariner health have not examined self-treatment habits or the incidence of minor health problems for which no care is sought from a health care provider. Our study examined patterns of minor medical problems and self-treatment among the crew of one submarine over a period of continued submergence for 101 d.Study data were obtained from three self-administered serial surveys of 122 medically screened U.S. Navy personnel onboard a submerged nuclear-powered submarine at the beginning, middle, and end of the study.During the first half of the study, 82% had medical complaints, most commonly runny nose, difficulty sleeping, and backache. In the second half, 77% listed complaints, most commonly difficulty sleeping. Despite readily available medical care, self-medication for minor unreported health problems was common, with use of products such as non-steroidal anti-inflammatory drugs, multi-vitamins, health supplements, topical preparations, and antihistamine/decongestants.Planning for medical care in isolated environments should include consideration of inreported minor medical problems and self-treatment patterns.

For more than a decade after the Gulf War, there has been concern that wartime exposures have resulted in significant morbidity among Gulf War veterans. After the end of the war, the Department of Veterans Affairs (VA) and the Department of Defense (DoD) initiated health registries to provide systematic clinical evaluations of Gulf War veterans who chose to participate. By September 1999, there were 32,876 participants in the DoD Comprehensive Clinical Evaluation Program and 70,385 participants in the VA Gulf War Registry Health Examination Program. We identified demographic and military service factors, as well as potential war-related exposures associated with subsequent registry participation after 10 years of observation. Veterans potentially exposed to oil well fire smoke, those near Khamisiyah, Reserve and National Guard, Army veterans, and veterans in the theater of operations during intense combat periods were most likely to elect to participate in a registry. These findings support the hypothesis that certain occupational factors and wartime exposures may influence subsequent health care-seeking behavior.

Background Nonresponse bias in a longitudinal study could affect the magnitude and direction of measures of association. We identified sociodemographic, behavioral, military, and health-related predictors of response to the first follow-up questionnaire in a large military cohort and assessed the extent to which nonresponse biased measures of association. Methods Data are from the baseline and first follow-up survey of the Millennium Cohort Study. Seventy-six thousand, seven hundred and seventy-five eligible individuals completed the baseline survey and were presumed alive at the time of follow-up; of these, 54,960 (71.6%) completed the first follow-up survey. Logistic regression models were used to calculate inverse probability weights using propensity scores. Results Characteristics associated with a greater probability of response included female gender, older age, higher education level, officer rank, active-duty status, and a self-reported history of military exposures. Ever smokers, those with a history of chronic alcohol consumption or a major depressive disorder, and those separated from the military at follow-up had a lower probability of response. Nonresponse to the follow-up questionnaire did not result in appreciable bias; bias was greatest in subgroups with small numbers. Conclusions These findings suggest that prospective analyses from this cohort are not substantially biased by non-response at the first follow-up assessment.

Background Self-reported medical history data are frequently used in epidemiological studies. Self-reported diagnoses may differ from medical record diagnoses due to poor patient-clinician communication, self-diagnosis in the absence of a satisfactory explanation for symptoms, or the "health literacy" of the patient. Methods The US Department of Defense military health system offers a unique opportunity to evaluate electronic medical records with near complete ascertainment while on active duty. This study compared 38 self-reported medical conditions to electronic medical record data in a large population-based US military cohort. The objective of this study was to better understand challenges and strengths in self-reporting of medical conditions. Results Using positive and negative agreement statistics for less-prevalent conditions, near-perfect negative agreement and moderate positive agreement were found for the 38 diagnoses. Conclusion This report highlights the challenges of using self-reported medical data and electronic medical records data, but illustrates that agreement between the two data sources increases with increased surveillance period of medical records. Self-reported medical data may be sufficient for ruling out history of a particular condition whereas prevalence studies may be best served by using an objective measure of medical conditions found in electronic healthcare records. Defining medical conditions from multiple sources in large, long-term prospective cohorts will reinforce the value of the study, particularly during the initial years when prevalence for many conditions may still be low.

Enlargement of the azygos vein is a well known anomaly in roentgenograms of patients with congestive heart failure (3). A report correlating the width of the azygos vein with venous pressure could not be found in the English literature. Since roentgenographic assessment of central venous pressure (CVP) would be useful in many clinical circumstances, we decided to determine the predictive value of this measurement. Materials and Method Initially, anteroposterior and oblique portable roentgenography of the chest was attempted on patients in the Intensive Care Unit (ICU) at the time CVP was recorded. An elective oblique roentgenogram and an additional overpenetrated anteroposterior view were necessary for better demonstration of the azygos vein. Because the maneuvers for these caused the patient much discomfort, the procedures were discontinued. Instead, anteroposterior films of patients in whom the CVP was measured within an hour of roentgenography were studied retrospectively. This study comprises a total ...