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Background: Military personnel are at increased risk for traumatic brain injury (TBI) from combat and non-combat exposures. Sequelae of moderate-to-severe TBI are well described, but the literature remains conflicted regarding whether mild TBI (mTBI) results in lasting brain injury and functional impairments. This study assessed risk for a range of neuropsychiatric disorders presenting after mTBI while adjusting for the potential confounds of depression and post-traumatic stress disorder (PTSD)., Methods: A historical prospective association study was conducted utilising electronic demographic, medical and military-specific data for over 49,000 active duty US Air Force service members (Airmen). This study utilised diagnostic codes considered by an expert panel to be indicative of mTBI to identify cases. Cox proportional hazards modelling calculated HRs for neuropsychiatric outcomes while controlling for varying lengths of follow-up and potentially confounding variables., Results: Airmen with mTBI were at increased risk for specific neuropsychiatric disorders compared with a similarly injured non-mTBI control group. HRs for memory loss/amnesia, cognitive disorders, schizophrenia, PTSD, and depression were significantly elevated and remained so for at least 6 months post-mTBI, even after eliminating those with previous neuropsychiatric diagnoses., Conclusions: mTBI was positively associated with neuropsychiatric disorders in this population of primarily young adult males; with increased HRs 6 months post-mTBI. The results support that mTBI is distinguished from moderate-to-severe TBI in terms of risk for developing neuropsychiatric disorders. Further, these findings suggest the importance of screening for psychiatric and cognitive disorders post-mTBI in general medical practice., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Objective: To prospectively examine the association between post-traumatic stress disorder (PTSD) and weight change., Methods: Longitudinal analysis techniques were used to examine data (2001-2008) from Millennium Cohort Study participants, consisting of U.S. service members and veterans. Using the PTSD Checklist-Civilian Version, PTSD was assessed as none, resolved, new onset, or persistent. Subsequent weight change was assessed as stable (≤3% loss or gain), >3% weight loss, >3% but <10% weight gain, and ≥10% weight gain., Results: Of the 38,352 participants, 2391 (6.2%) had PTSD (838 resolved, 1024 new onset, and 529 persistent), and 11% of participants subsequently had ≥10% weight gain. In multivariable models, PTSD was associated with higher odds of ≥10% weight gain (new onset OR: 1.44 [95% CI: 1.20-1.73]; persistent OR: 1.51 [CI: 1.17-1.96]; resolved OR: 1.30 [CI: 1.05-1.60]) compared with those without PTSD. New-onset and persistent PTSD were also associated with higher odds of >3% weight loss (OR: 1.41 [CI: 1.17-1.71]; OR: 1.42 [CI: 1.09-1.86], respectively)., Conclusions: PTSD is independently associated with a higher risk of weight gain and loss, the former of which leads to a higher prevalence of overweight and obesity and a higher risk of comorbidities associated with excessive body adiposity., (© 2015 The Obesity Society.)

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.

Objective: Mild traumatic brain injury (mTBI) accounts for more than 75% of traumatic brain injuries every year. This study examines the temporal association between non-blast mTBI and the onset of neurologic sequelae to illuminate risks of post-concussive syndrome, epilepsy and chronic pain., Methods: A large historical prospective study was conducted utilizing electronically-recorded demographic, medical and military-specific data for over half a million active duty US Air Force Airmen. This study utilized diagnostic codes to identify mTBI exposures, two control groups and three post-mTBI time periods. Adjusted hazard ratios (HRs) were calculated using Cox proportional hazards modelling., Results: HRs were higher when mTBI exposed Airmen were compared with the full cohort and lower when compared with the other injured group. When compared to the other injured group, mTBI was positively associated with epilepsy/recurrent seizure outcomes, post-concussive syndrome and pain disorders. HRs tended to be highest within the first 30 days and decreased over time., Conclusions: Findings support that mTBI may have a prolonged neurological impact. Findings are also likely generalizable to young adult populations with exposure to non-blast related mTBI, including civilians, as those included in this study were young adults with a high prevalence of recreational/sports and motor vehicle injuries.

Background: 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., Purpose: To compare self-reported depression symptoms on post-deployment health assessments with responses to the same depression questions on a research survey., Methods: 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., Results: 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)., Conclusions: 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., (Copyright © 2014 American Journal of Preventive Medicine. All rights reserved.)

Objectives: Combat exposure is known to increase the risk for mental disorders; however, less is known about the temporal relationship between mental disorders and alcohol misuse or smoking. To better understand these interrelationships, this study investigated mental disorders in association with hazardous drinking and cigarette smoking., Methods: Using data from a large population-based military cohort, standardized instruments were used to screen for posttraumatic stress disorder, depression, panic, and other anxiety syndromes. Self-reported use of cigarettes and hazardous drinking was also assessed. Subjects were classified as having "new-onset," "persistent," or "resolved" mental disorders and health risk behaviors on the basis of screening results from baseline to follow-up (n = 50,028). Multivariable logistic regression models were used to investigate temporal patterns between the development of mental disorders and the uptake of smoking or hazardous drinking., Results: The strongest associations of new-onset mental disorders were among those who newly reported smoking or hazardous drinking (odds ratio [OR], 1.82; 95% confidence interval [CI], 1.28-2.59 and OR, 2.49; 95% CI, 2.15-2.89, respectively), even after adjustment for combat deployment experience. In addition, persistent smokers and hazardous drinkers had elevated odds for developing a mental disorder at follow-up., Conclusions: This study demonstrates a positive association between the onset of mental disorders with the uptake of smoking and hazardous drinking and the likelihood that multiple temporal sequence patterns exist to explain the relationship between mental disorders and hazardous drinking and smoking. Clinical approaches to mitigate deployment-related mental disorders should include alcohol and tobacco-related assessments and interventions.

Background: Little is known regarding long-term performance decrements associated with mild Traumatic Brain Injury (mTBI). The goal of this study was to determine if individuals with an mTBI may be at increased risk for subsequent mishaps., Methods: Cox proportional hazards modeling was utilized to calculate hazard ratios for 518,958 active duty U.S. Air Force service members (Airmen) while controlling for varying lengths of follow-up and potentially confounding variables. Two non-mTBI comparison groups were used; the second being a subset of the original, both without head injuries two years prior to study entrance., Results: Hazard ratios indicate that the causes of increased risk associated with mTBI do not resolve quickly. Additionally, outpatient mTBI injuries do not differ from other outpatient bodily injuries in terms of subsequent injury risk., Conclusions: These findings suggest that increased risk for subsequent mishaps are likely due to differences shared among individuals with any type of injury, including risk-taking behaviors, occupations, and differential participation in sports activities. Therefore, individuals who sustain an mTBI or injury have a long-term risk of additional mishaps., Practical Applications: Differences shared among those who seek medical care for injuries may include risk-taking behaviors (Cherpitel, 1999; Turner & McClure, 2004; Turner, McClure, & Pirozzo, 2004), occupations, and differential participation in sports activities, among others. Individuals with an mTBI should be educated that they are at risk for subsequent injury. Historical data supported no lingering effects of mTBI, but more recent data suggest longer lasting effects. This study further adds that one of the longer term sequelae of mTBI may be an increased risk for subsequent mishap., (Copyright © 2013 National Safety Council and Elsevier Ltd. All rights reserved.)

Objective: To determine if deployment to recent military operations or other health, demographic, or military-related characteristics were associated with employment after military service., Methods: Former US active duty military service members participating in the Millennium Cohort Study, a population-based sample of US military personnel that began in July of 2001, were prospectively followed from the time of baseline health reporting to self-reported employment status after military separation., Results: Of the 9099 separated personnel meeting inclusion criteria, 17% reported unemployment after military service. In multivariable modelling, prior deployment experiences, with or without reported combat, and post-traumatic stress disorder (PTSD) were not significantly associated with employment status postservice. Among those who routinely retired from service with a pension, positive screens for depression (OR, 1.67; 95% CI, 1.05 to 2.63) and panic/anxiety (OR, 1.63; 95% CI, 1.10 to 2.43) were significantly associated with subsequent unemployment. Poor physical health, female sex, black race, lower education and disabling illnesses/injuries were also predictive of postservice unemployment., Conclusions: After stratifying for reason for military separation, mental disorders like depression or panic/anxiety and poor physical health may have greater impact than prior deployment experiences or PTSD on the ability to find or maintain employment postservice. These findings may guide support for veterans most in need of job placement services after military service.

Background: In light of increased concerns about suicide in the military, institutional review boards have mandated increased scrutiny of the final item on the depression screening tool, the PHQ-9, which asks about suicidal thoughts. Since real-time monitoring of all individual responses in most observational studies is not feasible, many investigators have adopted the PHQ-8, choosing to remove the ninth item. This study compares the performance of the PHQ-8 with the PHQ-9 in a population-based sample of military or nonmilitary subjects., Methods: The Millennium Cohort Study administers a self-reported questionnaire that includes the PHQ-9 at 3-year intervals to current and former U.S. military personnel. PHQ-9 responses of 143,705 Millennium Cohort members were investigated. Cross-sectional comparisons of the PHQ-9 and PHQ-8 and prospective analyses to detect a 5-unit change in these measures were performed., Results: Greater than substantial agreement was found between the PHQ-8 and 9 instruments (kappas, 0.966-0.974 depending on survey cycle). There was similarly high agreement between the PHQ-8 and 9 in detecting a 5-point increase (κ=0.987) or decrease (κ=0.984) in score., Limitations: One potential limitation of this study is that participants completed the PHQ-9, and PHQ-8 scores were extrapolated from the PHQ-9. In addition, the Millennium Cohort may not fully represent the U.S. military; though previous evaluations have shown the cohort to be a well-representative sample., Conclusions: Since excellent agreement was detected between the PHQ-8 and PHQ-9 instruments, the PHQ-8 would capture nearly all the same cases of depression as the PHQ-9 in populations similar to the one in this study., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Objective: Military personnel are at increased risk for traumatic brain injury (TBI) from combat and noncombat exposures. The sequelae of moderate to severe TBI are well described, but little is known regarding long-term performance decrements associated with mild TBI. Furthermore, while alcohol and drug use are well known to increase risk for TBI, little is known regarding the reverse pattern. The authors sought to assess possible associations between mild TBI and addiction-related disorders in active-duty U.S. military personnel., Method: A historical prospective study was conducted using electronically recorded demographic, medical, and military data for more than a half million active-duty U.S. Air Force service members. Cases were identified by ICD-9-CM codes considered by an expert panel to be indicative of mild TBI. Outcomes included ICD-9-CM diagnoses of selected addiction-related disorders. Cox proportional hazards modeling was used to calculate hazard ratios while controlling for varying lengths of follow-up and potential confounding variables., Results: Airmen with mild TBI were at increased risk for certain addiction-related disorders compared with a similarly injured non-mild TBI comparison group. Hazards for alcohol dependence, nicotine dependence, and nondependent abuse of drugs or alcohol were significantly elevated, with a consistent decrease over time., Conclusions: A novel finding of this study was the initial increased risk for addiction-related disorders that decreased with time, thus eroding war fighter performance in a military population. Moreover, these results suggest that mild TBI is distinguished from moderate to severe TBI in terms of timing of the risk, indicating that there is a need for screening and prevention of addiction-related disorders in mild TBI. Screening may be warranted in military troops as well as civilians at both short- and long-term milestones following mild TBI.

Limited prospective studies exist that evaluate the mental health status of military health care professionals who have deployed. This study used prospective data from the Millennium Cohort Study with longitudinal analysis techniques to examine whether health care professionals deployed in support of the operations in Iraq and Afghanistan were more likely to screen positive for new-onset posttraumatic stress disorder (PTSD) or depression after deployment than individuals from other occupations. Of 65,108 subjects included, 9,371 (14.4%) reported working as health care professionals. The rates of new positive screens for PTSD or depression were similar for those in health care occupations (4.7% and 4.3%) compared with those in other occupations (4.6% and 3.9%) for the first and second follow-up, respectively. Among military personnel deployed with combat experience, health care professionals did not have increased odds for new-onset PTSD or depression over time. Among deployed health care professionals, combat experience significantly increased the odds: adjusted odds ratio = 2.01; 95% confidence interval [1.06, 3.83] for new-onset PTSD or depression. These results suggest that combat experience, not features specific to being a health care professional, was the key exposure explaining the development of these outcomes., (Copyright © 2012 International Society for Traumatic Stress Studies.)

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.

Aims: To characterize smokeless tobacco initiation and persistence in relation to deployment, combat, occupation, smoking and mental health symptoms., Design: Prospective cohort, utilizing self-reported survey data from the Millennium Cohort Study., Setting: US military service members in all branches including active duty, reserve and National Guard., Participants: Population-based sample of 45,272 participants completing both baseline (July 2001-June 2003; n = 77,047) and follow-up (June 2004-January 2006; n = 55,021) questionnaires (follow-up response rate = 71.4%)., Measurements: Self-reported smokeless tobacco initiation and persistence., Findings: Over the study period, 72.4% did not deploy, 13.7% deployed without combat exposures and 13.9% deployed with combat exposures, while 1.9% were smokeless tobacco initiators and 8.9% were persistent users. The odds of initiation were greater for deployers with combat exposure [odds ratio (OR), 1.76; 95% confidence interval (CI), 1.49-2.09], deployers without combat exposure (OR, 1.31; 95% CI, 1.07-1.60) and those who deployed multiple times (OR, 1.67; 95% CI, 1.31-2.14), as well as in smoking recidivists/initiators (OR, 4.65; 95% CI, 3.82-5.66) and those reporting post-traumatic stress disorder symptoms (OR, 1.54; CI, 1.15-2.07). A similar pattern for higher odds of persistent use was observed for deployment and combat exposure, but not for smoking and mental health symptoms. Military occupation was not significantly associated with initiation or persistence., Conclusions: Deployment and combat exposure in the US military are associated with increased risk of smokeless tobacco initiation and persistence while smoking and symptoms of post-traumatic stress disorder increase the odds for initiation. Research is needed on aspects of military service amenable to the reduction or prevention of tobacco consumption., (Published 2011. This article is a U.S. Government work and is in the public domain in the USA.)

Objective: To investigate the association between US Navy individual augmentee (IA) deployers, who may lack the protective effects of unit cohesion and social support, and newly reported mental health., Methods: Responses from the Millennium Cohort Study questionnaires were examined for 2086 Navy deployers in this prospective exploratory study. Multivariable logistic regression was used to evaluate IA deployment and newly reported mental health symptoms., Results: After adjusting for covariates, IA deployment was not significantly associated with newly reported posttraumatic stress disorder (odds ratio = 1.02; 95% confidence interval: 0.53-1.95) or mental health symptoms (odds ratio = 1.03; 95% confidence interval: 0.66-1.60) compared with non-IA deployment., Conclusion: IA deployment was not associated with increased risk for posttraumatic stress disorder or mental health symptoms following deployment. It is likely that social isolation was not highly influential among Navy IAs in this study.

Purpose: The characteristics of U.S. military personnel who use dietary supplements have not been well described. This study aimed to determine whether deployment experience and physical activity were associated with the use of bodybuilding, energy, or weight-loss supplement among U.S. military personnel., Methods: Self-reported data from active-duty, Reserve, and National Guard participants of the Millennium Cohort Study collected from 2007-2008 (n = 106,698) on supplement use, physical activity, and other behavioral data were linked with deployment and demographic data. We used multivariable logistic regression sex-stratified models to compare the adjusted odds of each type of supplement use among those with deployment experience in support of operations in Iraq or Afghanistan and those engaged in aerobic or strength-training activities., Results: Overall, 46.7% of participants reported using at least one type of supplement, and 22.0% reported using multiple supplements. Male deployers were more likely to use bodybuilding supplements, whereas female deployers were more likely to use weight-loss supplements. Physically active and younger subjects reported all types of supplement use. Men and women reporting 5 or less hours of sleep per night were more likely to use energy supplements., Conclusions: The high prevalence of supplement use and important characteristics found to be associated with their use, including deployment, physical activity, and suboptimal sleep, suggest focus areas for future research and adverse event monitoring., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Most previous attempts to determine the psychological cost of military deployment have been limited by reliance on convenience samples, lack of pre-deployment data or confidentiality and cross-sectional designs., Aims: This study addressed these limitations using a population-based, prospective cohort of U.S. military personnel deployed in support of the operations in Iraq and Afghanistan., Method: The sample consisted of U.S. military service members in all branches including active duty, reserve and national guard who deployed once (n = 3393) or multiple times (n = 4394). Self-reported symptoms of post-traumatic stress were obtained prior to deployment and at two follow-ups spaced 3 years apart. Data were examined for longitudinal trajectories using latent growth mixture modelling., Results: Each analysis revealed remarkably similar post-traumatic stress trajectories across time. The most common pattern was low-stable post-traumatic stress or resilience (83.1% single deployers, 84.9% multiple deployers), moderate-improving (8.0%, 8.5%), then worsening-chronic post-traumatic stress (6.7%, 4.5%), high-stable (2.2% single deployers only) and high-improving (2.2% multiple deployers only). Covariates associated with each trajectory were identified., Conclusions: The final models exhibited similar types of trajectories for single and multiple deployers; most notably, the stable trajectory of low post-traumatic stress preto post-deployment, or resilience, was exceptionally high. Several factors predicting trajectories were identified, which we hope will assist in future research aimed at decreasing the risk of post-traumatic stress disorder among deployers.

Objectives: We examined the association of physical activity with prospectively assessed posttraumatic stress disorder (PTSD) symptoms in a military cohort., Methods: Using baseline and follow-up questionnaire data from a large prospective study of U.S. service members, we applied multivariable logistic regression to examine the adjusted odds of new-onset and persistent PTSD symptoms associated with light/moderate physical activity, vigorous physical activity, and strength training at follow-up., Results: Of the 38,883 participants, 89.4% reported engaging in at least 30 minutes of physical activity per week. At follow-up, those who reported proportionately less physical activity were more likely to screen positive for PTSD. Vigorous physical activity had the most consistent relationship with PTSD. Those who reported at least 20 minutes of vigorous physical activity twice weekly had significantly decreased odds for new-onset (odds ratio [OR] = 0.58, 95% confidence interval [CI] 0.49, 0.70) and persistent (OR = 0.59, 95% CI 0.42, 0.83) PTSD symptoms., Conclusions: Engagement in physical activity, especially vigorous activity, is significantly associated with decreased odds of PTSD symptoms among U.S. service members. While further longitudinal research is necessary, a physical activity component may be valuable to PTSD treatment and prevention programs.

Background: Complementary and Alternative Medicine use and how it impacts health care utilization in the United States Military is not well documented. Using data from the Millennium Cohort Study we describe the characteristics of CAM users in a large military population and document their health care needs over a 12-month period. The aim of this study was to determine if CAM users are requiring more physician-based medical services than users of conventional medicine., Methods: Inpatient and outpatient medical services were documented over a 12-month period for 44,287 participants from the Millennium Cohort Study. Equal access to medical services was available to anyone needing medical care during this study period. The number and types of medical visits were compared between CAM and non-CAM users. Chi square test and multivariable logistic regression was applied for the analysis., Results: Of the 44,287 participants, 39% reported using at least one CAM therapy, and 61% reported not using any CAM therapies. Those individuals reporting CAM use accounted for 45.1% of outpatient care and 44.8% of inpatient care. Individuals reporting one or more health conditions were 15% more likely to report CAM use than non-CAM users and 19% more likely to report CAM use if reporting one or more health symptoms compared to non-CAM users. The unadjusted odds ratio for hospitalizations in CAM users compared to non-CAM users was 1.29 (95% CI: 1.16-1.43). The mean number of days receiving outpatient care for CAM users was 7.0 days and 5.9 days for non-CAM users (p < 0.001)., Conclusions: Our study found those who report CAM use were requiring more physician-based medical services than users of conventional medicine. This appears to be primarily the result of an increase in the number of health conditions and symptoms reported by CAM users.

Although documentation that war inflicts psychological casualties dates back to the American Civil War and earlier, most research began after the Vietnam conflict, when studies focused on post-traumatic stress disorder (PTSD). With ongoing conflicts in Iraq and Afghanistan, there has been significant research to illuminate the epidemiology of war-related psychological casualties. Significant findings include an appreciation for the role combat plays in the development of mental disorders, including PTSD and traumatic brain injury (TBI). Recent research has endeavoured to understand and improve psychological resilience to temper potentially adverse mental health effects of military service in the theatre of combat operations. Over 2 million US service members have now deployed and returned over 3 million times to the Iraq and Afghanistan conflicts. Mental health providers in the Departments of Defense and Veterans Affairs healthcare systems have consequently observed steep increases in mental health service use among these personnel. The Departments have responded aggressively to bolster staffing levels, increase capacity, improve available services, and anticipate future needs. Scientists and clinicians continue efforts to understand the determinants, prevention, recognition, and treatment of combat-related mental disorders.

Background: Combat-intense, lengthy, and multiple deployments in Iraq and Afghanistan have characterized the new millennium. The US military's all-volunteer force has never been better trained and technologically equipped to engage enemy combatants in multiple theaters of operations. Nonetheless, concerns over potential lasting effects of deployment on long-term health continue to mount and are yet to be elucidated. This report outlines how findings from the first 7 years of the Millennium Cohort Study have helped to address health concerns related to military service including deployments., Methods: The Millennium Cohort Study was designed in the late 1990s to address veteran and public concerns for the first time using prospectively collected health and behavioral data., Results: Over 150,000 active-duty, reserve, and National Guard personnel from all service branches have enrolled, and more than 70% of the first 2 enrollment panels submitted at least 1 follow-up survey. Approximately half of the Cohort has deployed in support of operations in Iraq and Afghanistan., Conclusion: The Millennium Cohort Study is providing prospective data that will guide public health policymakers for years to come by exploring associations between military exposures and important health outcomes. Strategic studies aim to identify, reduce, and prevent adverse health outcomes that may be associated with military service, including those related to deployment.

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: Prostate cancer is the most common cancer among US men, however, the etiology remains unclear. Yet, one consistency is that black non-Hispanic men are at increased risk for prostate cancer compared to white, non-Hispanic men. The goal of this study was to assess relations between demographic and other potential prostate cancer risk factors in the context of the US military healthcare system, which provides equal access to all US servicemen., Methods: Military healthcare and demographic data were used to describe risk factors for prostate cancer in the US military from September 1993 to September 2003. Cox's proportional hazards regression was employed to model the time to prostate cancer hospitalization., Results: Four hundred eight first prostate cancer hospitalizations were identified among 2,761,559 servicemen. The adjusted rate per 100,000 persons rose from 1.41 to 3.62 for white non-Hispanic men and 1.43 to 6.08 for black non-Hispanic men by the end of the study. The increasing incidence over time for combined race/ethnic groups was similar to trends reported in the Surveillance, Epidemiology, and End Results Program for the US civilian population. No association was observed between occupation and prostate cancer hospitalization. However, black non-Hispanic men were at increased risk compared with white non-Hispanic men (hazard ratio = 2.72, 95% confidence interval: 2.12, 3.49)., Conclusions: No association was observed between occupation and prostate cancer hospitalization. In this relatively young cohort, black non-Hispanic race/ethnicity was found to be predictive of prostate cancer, and this association existed regardless of access to care and socioeconomic status.

Background: Injuries, one of the leading public health problems in an otherwise healthy military population, affect operational readiness, increase healthcare costs, and result in disabilities and fatalities. This paper describes a systematic, data-driven, injury prevention-decision making process to rank potential injury prevention targets., Methods: Medical surveillance and safety report data on injuries for 2004 were reviewed. Nonfatal injury diagnoses (ICD-9-CM codes) obtained from the Defense Medical Surveillance System were ranked according to incident visit frequency and estimated limited duty days. Data on the top five injury types resulting in the greatest estimated limited duty days were matched with hospitalization and Service Safety Centers' accident investigation data to identify leading causes. Experts scored and ranked the causes using predetermined criteria that considered the importance of the problem, preventability, feasibility, timeliness of intervention establishment/results, and ability to evaluate. Department of Defense (DoD) and Service-specific injury prevention priorities were identified., Results: Unintentional injuries lead all other medical conditions for number of medical encounters, individuals affected, and hospital bed days. The top ten injuries resulted in an estimated 25 million days of limited duty. Injury-related musculoskeletal conditions were a leading contributor to days of limited duty. Sports and physical training were the leading cause, followed by falls., Conclusions: A systematic approach to injury prevention-decision making supports the DoD's goal of ensuring a healthy, fit force. The methodology described here advances this capability. Immediate follow-up efforts should employ both medical and safety data sets to identify and monitor injury prevention priorities., (Published by Elsevier Inc.)

Objective: We investigated relations between deployment and new-onset depression among US service members recently deployed to the wars in Iraq and Afghanistan., Methods: We included 40 219 Millennium Cohort Study participants who completed baseline and follow-up questionnaires and met inclusion criteria. Participants were identified with depression if they met the Primary Care Evaluation of Mental Disorders Patient Health Questionnaire criteria for depression at follow-up, but not at baseline., Results: Deployed men and women with combat exposures had the highest onset of depression, followed by those not deployed and those deployed without combat exposures. Combat-deployed men and women were at increased risk for new-onset depression compared with nondeployed men and women (men: adjusted odds ratio [AOR]=1.32; 95% confidence interval [CI]=1.13, 1.54; women: AOR=2.13; 95% CI=1.70, 2.65). Conversely, deployment without combat exposures led to decreased risk for new-onset depression compared with those who did not deploy (men: AOR=0.66; 95% CI=0.53, 0.83; women: AOR=0.65; 95% CI=0.47, 0.89)., Conclusions: Deployment with combat exposures is a risk factor for new-onset depression among US service members. Post-deployment screening may be beneficial for US service members exposed to combat.

High-stress situations, such as combat deployments, are a potential risk factor for hypertension. Although stress is postulated to increase blood pressure, the underlying role of stress on hypertension is not well established. We sought to determine the relations between combat deployment-induced stress and hypertension. The Millennium Cohort baseline questionnaire (2001-2003) was completed by 77,047 US active-duty and Reserve/National Guard members. Follow-up was completed by 55,021 responders approximately 3 years later (2004-2006). Multivariable logistic regression was used to estimate the 3-year risk of newly reported hypertension, adjusting for general and mental health, demographics, and occupational and behavioral characteristics. After applying exclusion criteria, our analyses included 36 061 service members. Subanalyses of deployers included 8829 participants. Newly reported hypertension was identified in 6.9% of the cohort between baseline and follow-up, many of whom had deployed on military operations in support of the conflicts in Iraq and Afghanistan. After adjusting, deployers who experienced no combat exposures were less likely to report hypertension than nondeployers (odds ratio: 0.77; 95% CI: 0.67 to 0.89). Among deployers, those reporting multiple combat exposures were 1.33 times more likely to report hypertension compared with noncombat deployers (95% CI: 1.07 to 1.65). Although military deployers, in general, had a lower incidence of hypertension than nondeployers, deployment with multiple stressful combat exposures appeared to be a unique risk factor for newly reported hypertension.

Purpose: To describe medical symptom and condition reporting in relation to complementary and alternative medicine (CAM) use among members of the US military., Methods: CAM was defined as health treatments not widely taught at US medical schools or typically available at US hospitals. By using data from the Millennium Cohort Study, we included participants who completed a survey from 2004 to 2006 (n=86,131) as part of this cross-sectional analysis in which we sought to identify demographic characteristics and types of health-related symptoms and conditions associated with CAM use. Chi-square tests were used to compare health assessed by self-reported symptoms and conditions among those not reporting CAM use with those reporting practitioner-assisted or self-administered CAM., Results: Of 86,131 participants, 30% reported using at least one practitioner-assisted CAM therapy, 27% reported using at least one self-administered CAM therapy, whereas 59% did not report using any CAM therapy. Both women and men who used CAM reported a greater proportion of specific health conditions and health-related symptoms compared with those not reporting CAM use (p<0.05)., Conclusions: These findings illustrate that a relatively young adult occupational cohort of military personnel using CAM therapies also report multiple comorbidities which may indicate chronic illness management and poorer overall health.

Objective: To determine if baseline functional health status, as measured by SF-36 (veterans), predicts new onset symptoms or diagnosis of post-traumatic stress disorder among deployed US military personnel with combat exposure., Design: Prospective cohort analysis., Setting: Millennium Cohort., Participants: Combat deployed members who completed baseline (2001-3) and follow-up (2004-6) questionnaires. Self reported and electronic data used to examine the relation between functional health and post-traumatic stress disorder., Main Outcome Measures: New onset post-traumatic stress disorder as measured by either meeting the DSM-IV criteria with the 17 item post-traumatic stress disorder checklist-civilian version or self report of a physician diagnosis at follow-up with the absence of both at baseline., Results: Of the 5410 eligible participants, 395 (7.3%) had new onset symptoms or diagnosis of post-traumatic stress disorder at the time of follow-up. Individuals whose baseline mental or physical component summary scores were below the 15th centile had two to three times the risk of symptoms or a diagnosis of post-traumatic stress disorder by follow-up compared with those in the 15th to 85th centile. Of those with new onset symptoms or diagnosis of post-traumatic stress disorder, over half (58%) of cases occurred among participants with scores below the 15th centile at baseline., Conclusions: Low mental or physical health status before combat exposure significantly increases the risk of symptoms or diagnosis of post-traumatic stress disorder after deployment. More vulnerable members of a population could be identified and benefit from interventions targeted to prevent new onset post-traumatic stress disorder.

The effect of military deployments to combat environments on disordered eating and weight changes is unknown. Using longitudinal data from Millennium Cohort Study participants who completed baseline (2001-2003) and follow-up (2004-2006) questionnaires (n=48,378), the authors investigated new-onset disordered eating and weight changes in a large military cohort. Multivariable logistic regression was used to compare these outcomes among those who deployed and reported combat exposures, those who deployed but did not report combat exposures, and those who did not deploy in support of the wars in Iraq and Afghanistan. Deployment was not significantly associated with new-onset disordered eating in women or men, after adjustment for baseline demographic, military, and behavioral characteristics. However, in subgroup comparison analyses of deployers, deployed women reporting combat exposures were 1.78 times more likely to report new-onset disordered eating (95% confidence interval: 1.02, 3.11) and 2.35 times more likely to lose 10% or more of their body weight compared with women who deployed but did not report combat exposures (95% confidence interval: 1.17, 4.70). Despite no significant overall association between deployment and disordered eating and weight changes, deployed women reporting combat exposures represent a subgroup at higher risk for developing eating problems and weight loss.

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.

This study explores adverse events severe enough to warrant hospitalization that may have been associated with receiving the smallpox vaccine in conjunction with military service. Cox proportional hazards modeling was used to identify the risk of hospitalization among US active-duty military personnel during a 1-year period following receipt of the smallpox vaccine. The reference group consisted of active-duty military personnel who also received the smallpox vaccine after the conclusion of their health care observation period, allowing for comparison to a temporally and demographically similar population. The risk of hospitalization was slightly elevated among the postvaccine group for any-cause hospitalization and for hospitalization in several broad diagnostic categories. Hospitalizations for asthma, autoimmune diseases, and myopericarditis, were more likely in the postvaccine group. The increased risk of hospitalization for varied outcomes does not necessarily imply a cause-effect relationship, but it does offer areas for more focused study, using longitudinal data to explore the long-term impact of smallpox vaccination on the health of young adults.

In December 2002, the Department of Defense re-instituted smallpox vaccination for US military forces following growing concerns that smallpox might be employed as a bioterrorist weapon. More than one million service members have been given the smallpox vaccine since 2002, although there have been concerns about the safety of the vaccine. Using a large self-reported prospective database, this analysis investigated a wide variety of self-reported health outcomes and possible association with smallpox vaccination. After confirming self-reported vaccination history with electronic vaccine data, 40,472 individuals were included in the analyses, 8,793 of whom received the smallpox vaccine and 31,679 who did not. No significant adverse associations between smallpox vaccination and self-reported health outcomes, including mental and physical functioning, cardiovascular diseases, and autoimmune disorders, were found. These findings complement studies that utilize other data sources, such as electronic hospitalization records, and may be reassuring to health care providers and those who receive the smallpox vaccination.

Background: The US military is currently involved in large, lengthy, and complex combat operations around the world. Effective military operations require optimal health of deployed service members, and both mental and physical health can be affected by military operations., Methods: Baseline data were collected from 77,047 US service members during 2001-2003 as part of a large, longitudinal, population-based military health study (the Millennium Cohort Study). The authors calculated unadjusted, adjusted, and weighted means for the Medical Outcomes Study Short Form 36-item Survey for Veterans physical (PCS) and mental component summary (MCS) scores over a variety of demographic and military characteristics at baseline., Results: The unadjusted mean PCS and MCS scores for this study were 53.4 (95% confidence interval: 53.3-53.4) and 52.8 (95% confidence interval: 52.7-52.9). Average PCS and MCS scores were slightly more favorable in this military sample compared to those of the US general population of the same age and sex. Factors independently associated with more favorable health status included male gender, being married, higher educational attainment, higher military rank, and Air Force service. Combat specialists had similar health status compared to other military occupations. Having been deployed to Southwest Asia, Bosnia, or Kosovo between 1998 and 2000 was not associated with diminished health status., Conclusion: The baseline health status of this large population-based military cohort is better than that of the US general population of the same age and sex distribution over the same time period, especially in older age groups. Deployment experiences during the period of 1998-2001 were not associated with decreased health status. These data will serve as a useful reference for other military health studies and for future longitudinal analyses.

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.

Objectives: The 12-month prevalence of common mental illnesses in the United States is estimated to be 26%, accounting for an increasing fraction of all disability in the general population. The U.S. military is a unique group involved in response and defense during times of conflicts and disasters. The mental health of service members affects organizational productivity and effectiveness and is of great importance to the health of U.S. military members and public health in general., Study Design and Setting: In the present report, the authors describe the baseline prevalence of mental disorders in a large U.S. military cohort, the Millennium Cohort, established for a 22-year longitudinal study of the health effects of military service. Using crude and weighted prevalence and multivariable logistic regression, the mental health morbidity of the Millennium Cohort is reported for various demographics., Results: These analyses suggest that although the cohort compares favorably to other populations, there are military subpopulations, including women, younger, less educated, single, white, short-term service, enlisted, and Army members, who are at greater odds for some mental disorders., Conclusion: With ongoing U.S. involvement in combat operations around the world, these baseline data are essential to assessing long-term mental health morbidity in U.S. military service members.

The safety of mefloquine has not been well described in military populations. This study used standard military databases for mefloquine prescriptions and hospitalizations to investigate mefloquine safety among US service members from 2002 through 2004. Mefloquine-prescribed and deployed personnel (N = 8,858) were compared with two reference groups. The reference groups comprised US service members who were not prescribed mefloquine and resided in Europe or Japan (N = 156,203) or had been otherwise deployed (N = 232,381). In comparison with active-duty US service members residing in Europe or Japan, mefloquine-prescribed service members were at statistically significant decreased hazard for any-cause hospitalization, as well as diseases of the respiratory and digestive systems, musculoskeletal system and connective tissue diseases, injuries and poisonings, ill-defined conditions, and mood disorders. These results suggest there is no association between mefloquine prescriptions and severe health effects, as measured by hospitalizations, across a wide range of outcomes.

Background: The proportion of women in the U.S. military is increasing, and they are being selected into jobs that are more combat related. However, the mental health effects of working in combat support occupations among military women have not been previously evaluated., Methods: Active-duty enlisted Navy and Marine Corps women in combat support (n = 10,299) and noncombat support (n = 63,478) occupations were followed for 2 years between January 1, 1994, and August 31, 2001. Hospitalization diagnoses were examined and organized into eight categories of mental disorders; Cox proportional hazards modeling was used to describe these outcomes., Results: Women in combat support occupations were found to be significantly less likely to be hospitalized for a mental disorder than women in all other military occupations., Conclusions: These results are reassuring but may be confounded by a healthy worker selection effect. Further studies are needed to assess how service in combat support occupations affects the long-term health of U.S. military women.

Myopericarditis has been a rare or unrecognized event after smallpox vaccinations with the New York City Board of Health strain of vaccinia virus (Dryvax; Wyeth Laboratories, Marietta, Pennsylvania). In this article, the authors report an attributable incidence of at least 140 clinical cases of myopericarditis per million primary smallpox vaccinations with this strain of vaccinia virus. Fifty-eight males and one female aged 21-43 years with confirmed or probable acute myopericarditis were detected following vaccination of 492,730 US Armed Forces personnel from December 15, 2002, through September 30, 2003. The cases were identified through sentinel reporting to military headquarters, active surveillance using the Defense Medical Surveillance System, or reports to the Vaccine Adverse Event Reporting System. The observed incidence (16.11/100,000) of myopericarditis over a 30-day observation window among 347,516 primary vaccinees was nearly 7.5-fold higher than the expected rate of 2.16/100,000 (95% confidence interval: 1.90, 2.34) among nonvaccinated, active-duty military personnel, while the incidence of 2.07/100,000 among 145,155 revaccinees was not statistically different from the expected background rate. The cases were predominantly male (58/59; 98.3%) and White (51/59; 86.4%), both statistically significant associations (p = 0.0147 and p = 0.05, respectively).

For the Millennium Cohort Study Team Little is known of the association between military occupation and posttraumatic stress disorder (PTSD) or depression and the relations between these conditions and lost workdays. The objective of this study was to determine if military occupation is associated with PTSD or depression. A secondary objective was to determine if PTSD or depression was associated with lost workdays. Occupations for U.S. Navy and Marine Corps personnel were classified according to Department of Defense definitions. The 17-item PTSD Checklist-Civilian version was used to assess PTSD, whereas depression status was assessed using the nine-item Patient Health Questionnaire. Navy personnel in service and supply occupations were at greater odds of reporting PTSD, whereas those serving in health care were at greater odds of reporting depression. Individuals reporting new-onset or persistent PTSD or depression had about twice the odds of reporting lost workdays. PTSD and depression were positively associated with lost workdays, suggesting that early identification and management of these conditions may improve readiness. [ABSTRACT FROM PUBLISHER]