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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:: 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. Language: en

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.

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.

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.

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.

Background Recently, there has been concern that service members deploying in support of the current operations in Iraq and Afghanistan may have higher odds of developing chronic diseases, such as lupus or rheumatoid arthritis, as a result of environmental and occupational exposures that have been associated with these diseases in the general US population. One such exposure garnering much attention from media and veterans groups suggest smoke from open-air burning of trash and other waste in theater is contributing to widespread illness. Methods Of the 63,590 participants who completed both the 2004?2006 and 2007?2008 questionnaires, exclusions included those who affirmatively reported disease to all provider-diagnosed medical conditions, reported ever having lupus or rheumatoid arthritis prior to or on the 2004?2006 survey assessment, did not complete the outcome responses, were in the Navy or Marine Corps, never deployed between 2003 and 2007?2008 survey assessments, experienced a first deployment or exposure to a documented burn pit after newly reporting either outcome, or were missing any covariates of interest. Results 3201 and 3145 participants from the respective lupus and rheumatoid arthritis study populations identified with at least one deployment to an area within a 3-mile radius of a documented open-air burn pit. After adjustment, proximity to a documented 3-mile burn pit was not significantly associated with rheumatoid arthritis or lupus in general. Conclusions Results indicate deployers exposed to documented burn pits in the combined three-camp analysis were not at an elevated risk of lupus or rheumatoid arthritis.

Current deployments to Iraq and Afghanistan have generated concern regarding the association between combat deployment and mental health disorders. Those deploying on an individual assignment (IA) may be at increased risk for mental health challenges. The objective of this research is to describe new-onset of self-reported posttraumatic stress disorder (PTSD), depression, anxiety, and alcohol disorders in the Millennium Cohort and assess the relationship between IA deployment and mental health morbidity. Millennium Cohort Study members deployed for the first time in support of the wars in Iraq and Afghanistan between baseline and follow-up were included in these analyses (n = 12 952). Women deployed on an IA with reported combat exposures were at greatest risk of any mental health outcome (odds ratio [OR] 4.04; 95% confidence interval [CI], 1.90-8.62), PTSD (OR 8.24; 95% CI, 2.88-23.61), or alcohol abuse (OR 3.20; 95% CI, 1.11-9.25) postdeployment compared with regular deployed women without combat exposures. This investigation contributes insight into which additional services those deployed on an IA may benefit from to prevent mental health challenges. Military women deployed on IA, in particular, may benefit from additional time and efforts to increase social support and unit cohesion before deployment.

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.

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.

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.

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 ≈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 There is significant public and veteran concerns over the impact of military deployments to Iraq and Afghanistan on veterans' health. This study investigates morbidity among deployers by uniquely comparing after-deployment hospitalizations to before-deployment hospitalizations and hospitalizations among nondeployers. Methods To compare after-deployment with before-deployment rates of morbidity, we examined active-duty military personnel who deployed for the first time in support of the current conflicts in 2003 or 2004 and had at least 12 months of service before deployment. We also compared the after-deployment hospitalizations to hospitalizations of personnel serving on active duty from May 2002 through May 2004 without a deployment from September 2001 through August 2006. This historical prospective investigation utilized Cox's proportional hazards time-to-event modeling. Hospitalizations for any cause and hospitalizations based on 14 broad diagnostic categories were examined. Results After adjusting for demographic and occupational variables, the after-deployment risk for any-cause hospitalization was greater in comparison with before-deployment (hazard ratio, 1.57; 95% CI, 1.48–1.66) but lower in comparison with nondeployers (HR, 0.95, 95% CI, 0.92–0.98). Conclusions Active-duty service members have an increased risk of hospitalization after deployment compared with before deployment but a lower risk when compared with nondeployers.

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.

Background The stress of military deployment may compound occupational stress experienced in the military and manifest in maladaptive coping behaviors such as cigarette smoking. The current study describes new smoking among never-smokers, smoking recidivism among past smokers, and change in daily smoking among smokers in relation to military deployment. Methods The Millennium Cohort is a 21-year longitudinal study. The current analysis utilized participants (N=48,304) who submitted baseline data (July 2001–June 2003) before the current conflicts in Iraq and Afghanistan and follow-up data (June 2004–January 2006) on health measures. New smoking was identified among baseline never-smokers, smoking recidivism among baseline past smokers, and increased or decreased daily smoking among baseline smokers. Analyses were conducted March 2007–April 2007. Results Among never-smokers, smoking initiation was identified in 1.3% of nondeployers and 2.3% of deployers. Among past smokers, smoking resumption occurred in 28.7% of nondeployers and 39.4% of those who deployed. Smoking increased 44% among nondeployers and 57% among deployers. Those who deployed and reported combat exposures were at 1.6 times greater odds of initiating smoking among baseline never-smokers (95% CI=1.2, 2.3) and at 1.3 times greater odds of resuming smoking among baseline past smokers when compared to those who did not report combat exposures. Other deployment factors independently associated with postdeployment smoking recidivism included deploying for >9 months and deploying multiple times. Among those who smoked at baseline, deployment was not associated with changes in daily amount smoked. Conclusions Military deployment is associated with smoking initiation and, more strongly, with smoking recidivism, particularly among those with prolonged deployments, multiple deployments, or combat exposures. Prevention programs should focus on the prevention of smoking relapse during or after deployment.

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.

Results obtained from self-reported health data may be biased if those being surveyed respond differently based on health status. This study was conducted to investigate if health, as measured by health care use preceding invitation, influenced response to invitation to a 21-year prospective study, the Millennium Cohort Study. Inpatient and outpatient diagnoses were identified among more than 68,000 people during a one-year period prior to invitation to enroll. Multivariable logistic regression defined how diagnoses were associated with response. Days spent hospitalized or in outpatient care were also compared between responders and nonresponders. Adjusted odds of response to the questionnaire were similar over a diverse range of inpatient and outpatient diagnostic categories during the year prior to enrollment. The number of days hospitalized or accessing outpatient care was very similar between responders and nonresponders. Study findings demonstrate that, although there are some small differences between responders and nonresponders, prior health care use did not affect response to the Millennium Cohort Study, and it is unlikely that future study findings will be biased by differential response due to health status prior to enrollment invitation.

PURPOSE: Studies researching service members’ health after deployment have relied on self-reported deployment history, although validity of these data remains unknown. This study compared self-reported and electronic deployment data and explored differences in functional health. METHODS: Self-reported and military deployment data were compared for more than 51,000 participants enrolled in the Millennium Cohort Study (2004–2006). Kappa statistics were used to measure agreement. Analysis of variance was used to assess functional health, as measured by the Medical Outcomes Study Short Form 36-Item Health Survey for Veterans (SF-36V). RESULTS: Of 51,741 participants who completed the initial deployment question, objective records and self-report agreed in 47,355 (92%). Agreement was substantial for deployment status, frequency, and number of deployments (kappa Z 0.81, 0.71, and 0.61, respectively). Deployment start dates agreed within 1 month for 82% of participants confirmed as deployed once. Participants’ Mental and Physical Component Summary scores from the SF-36V did not differ by agreement level. CONCLUSIONS: These findings indicate substantial agreement between self-reported and objective deployment information and no clinically meaningful differences in functional health for the small proportion with inconsistent deployment information. These findings should be reassuring to investigators who examine military deployment as a determinant of future health. Ann Epidemiol 2007;17:976–982. 2007 Elsevier Inc. All rights reserved.

Almost 60% of American households were connected to the Internet in 2001, when the Millennium Cohort Study, the largest longitudinal study ever undertaken by the Department of Defense, was launched. To facilitate survey completion, increase data integrity, and encourage cohort retention while maintaining the highest standards of participant privacy, an online questionnaire was made available on the World Wide Web in addition to a traditional paper questionnaire sent via US mail. Over 50% of 77,047 participants chose to enroll in the study via the Web, affording substantial cost savings to the project. Using multivariable logistic regression, the authors compared the demographic and health characteristics of Web responders with those of paper responders. Web responders were slightly more likely to be male, to be younger, to have a high school diploma or college degree, and to work in information technology or another technical occupation. Web responders were more likely to be obese and to smoke more cigarettes and were less likely to be problem alcohol drinkers and to report occupational exposures. Question completion rates were 98.3%, on average, for both Web and paper responders. Web responders provided more complete contact information, including their e-mail addresses. These results demonstrate the value of survey research conducted over the Internet in concert with traditional mail survey strategies.

Purpose The Millennium Cohort Study began in 2001 using mail and Internet questionnaires to gather occupational and environmental exposure, behavioral risk factor, and health outcome data from a large, population-based US military cohort. Standardized instruments, including the Patient Health Questionnaire, the Medical Outcomes Study Short Form-36 for Veterans, and the Posttraumatic Stress Disorder (PTSD) Checklist–Civilian Version, have been validated in various populations. The purpose of this study was to investigate internal consistency of standardized instruments and concordance of responses in a test-retest setting. Methods Cronbach alpha coefficients were used to investigate the internal consistency of standardized instruments among 76,742 participants. Kappa statistics were calculated to measure stability of aggregated responses in a subgroup of 470 participants who voluntarily submitted an additional survey within 6 months of their original submission. Results High internal consistency was found for 14 of 16 health components, with lower internal consistency found among two alcohol components. Substantial test-retest stability was observed for stationary variables, while moderate stability was found for more dynamic variables that measured conditions with low prevalence. Conclusions These results substantiate internal consistency and stability of several standard health instruments applied to this large cohort. Such reliability analyses are vital to the integrity of long-term outcome studies.

Background In 1998, the United States Department of Defense initiated the Anthrax Vaccine Immunization Program. Concerns about vaccine-related adverse health effects followed, prompting several studies. Although some studies used self-reported vaccination data, the reliability of such data has not been established. The purpose of this study was to compare self-reported anthrax vaccination to electronic vaccine records among a large military cohort and to evaluate the relationship between vaccine history and health outcome data. Methods Between September 2005 and February 2006 self-reported anthrax vaccination was compared to electronic records for 67,018 participants enrolled in the Millennium Cohort Study between 2001 and 2003 using kappa statistics. Multivariable modeling investigated vaccination concordance as it pertains to subjective health (functional status) and objective health (hospitalization) metrics. Results Greater than substantial agreement (kappa=0.80) was found between self-report and electronic recording of anthrax vaccination. Of all participants with electronic documentation of anthrax vaccination, 98% self-reported being vaccinated; and of all participants with no electronic record of vaccination, 90% self-reported not receiving a vaccination. There were no differences between vaccinated and unvaccinated participants in overall measures of health. Only the subset of participants who self-reported anthrax vaccination, but had no electronic confirmation, differed from others in the cohort, with consistently lower measures of health as indicated by Medical Outcomes Study 36-Item Short Form Health Survey for Veterans (SF-36V) scores. Conclusions These results indicate that military members accurately recall their anthrax vaccinations. Results also suggest that anthrax vaccination among Millennium Cohort participants is not associated with self-reported health problems or broad measures of health problems severe enough to require hospitalization. Service members who self-report vaccination with no electronic documentation of vaccination, however, report lower measures of physical and mental health and deserve further research.

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.

Much attention has been given to the impact of deployment on the health of veterans from the 1991 Gulf War. Whereas increases in self-reported symptoms have been common, no specific exposures have been implicated. Some have suggested that stress from deployment is the chief cause for multisymptom conditions among Gulf War veterans, but comparisons with the health of other recent deployers have not been made. We sought to examine the impact of several large military deployments on hospitalization experience. Hospitalization records were examined for all active duty personnel deployed exclusively to the Gulf War, Southwest Asia after the Gulf War, or Bosnia. Cox's hazard modeling was used to assess time until first post-deployment hospitalization, separation from active duty, or December 31, 2000, whichever occurred first, while controlling for influential covariates and temporal changes. Personnel deployed to Southwest Asia after the 1991 Gulf War were at a slight increased risk for any-cause hospitalization and for 3 of the 14 major diagnostic categories when compared with veterans of the 1991 Gulf War. Personnel deployed to Bosnia were at a decreased risk for any-cause hospitalization and 12 of the 14 major diagnostic categories when compared with Gulf War veterans. These findings do not fully explain the complexity of postdeployment health experiences. Although the risk for hospitalization may be associated with regional deployment, it is unlikely that Gulf War veterans are at greater risk of hospitalization due to a specific exposure-related disease.

There is much concern over the potential for short- and long-term adverse mental health effects caused by the terrorist attacks on September 11, 2001. This analysis used data from the Millennium Cohort Study to identify subgroups of US military members who enrolled in the cohort and reported their mental health status before the traumatic events of September 11 and soon after September 11. While adjusting for confounding, multivariable logistic regression, analysis of variance, and multivariate ordinal, or polychotomous logistic regression were used to compare 18 self-reported mental health measures in US military members who enrolled in the cohort before September 11, 2001 with those military personnel who enrolled after September 11, 2001. In contrast to studies of other populations, military respondents reported fewer mental health problems in the months immediately after September 11, 2001.

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.

To prospectively examine the association between post-traumatic stress disorder (PTSD) and weight change.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% but10% weight gain, and ≥10% weight gain.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 of3% weight loss (OR: 1.41 [CI: 1.17-1.71]; OR: 1.42 [CI: 1.09-1.86], respectively).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.

Background— The recent conflicts in Iraq and Afghanistan have exposed thousands of service members to intense stress, and as a result, many have developed posttraumatic stress disorder (PTSD). The role of military deployment experiences and PTSD in coronary heart disease (CHD) is not well defined, especially in young US service members with recent combat exposure. Methods and Results— We conducted a prospective cohort study to investigate the relationships between wartime experiences, PTSD, and CHD. Current and former US military personnel from all service branches participating in the Millennium Cohort Study during 2001 to 2008 (n=60 025) were evaluated for newly self-reported CHD. Electronic medical record review for International Classification of Diseases, Ninth Revision, Clinical Modification codes for CHD was conducted among a subpopulation of active duty members (n=23 794). Logistic regression models examined the associations between combat experiences and PTSD with CHD with adjustment for established CHD risk factors. A total of 627 participants (1.0%) newly reported CHD over an average of 5.6 years of follow-up. Deployers with combat experiences had an increased odds of newly reporting CHD (odds ratio, 1.63; 95% confidence interval, 1.11–2.40) and having a diagnosis code for new-onset CHD (odds ratio, 1.93; 95% confidence interval, 1.31–2.84) compared with noncombat deployers. Screening positive for PTSD symptoms was associated with self-reported CHD before but not after adjustment for depression and anxiety and was not associated with a new diagnosis code for CHD. Conclusions— Combat deployments are associated with new-onset CHD among young US service members and veterans. Experiences of intense stress may increase the risk for CHD over a relatively short period among young adults.

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

Background: Previous studies have examined the prevalence, risk factors, and health correlates of sexual stressors in the military, but have been limited to specific subpopulations. Furthermore, little is known about sexual stressors’ occurrence and their correlates in relation to female troops deployed to the current operations in Iraq and Afghanistan. Methods: Using longitudinal data from Millennium Cohort participants, the associations of recent deployment as well as other individual and environmental factors with sexual harassment and sexual assault were assessed among U.S. female military personnel. Multivariable analyses were used to investigate the associations. Findings: Of 13,262 eligible participants, 1,362 (10.3%) reported at least one sexual stressor at follow-up. Women who deployed and reported combat experiences were significantly more likely to report sexual harassment (odds ratio [OR], 2.20; 95% confidence interval [CI], 1.84–2.64) or both sexual harassment and sexual assault (OR, 2.47; 95% CI, 1.61–3.78) compared with nondeployers. In addition, significant risk factors for sexual stressors included younger age, recent separation or divorce, service in the Marine Corps, positive screen for a baseline mental health condition, moderate/ severe life stress, and prior sexual stressor experiences. Conclusions: Although deployment itself was not associated with sexual stressors, women who both deployed and reported combat were at a significantly increased odds for sexual stressors than other female service members who did not deploy. Understanding the factors associated with sexual stressors can inform future policy and prevention efforts to eliminate sexual stressors. Copyright 2013 by the Jacobs Institute of Women’s Health. Published by Elsevier Inc.

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.

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.

To characterize smokeless tobacco initiation and persistence in relation to deployment, combat, occupation, smoking and mental health symptoms.Prospective cohort, utilizing self-reported survey data from the Millennium Cohort Study.US military service members in all branches including active duty, reserve and National Guard.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%).Self-reported smokeless tobacco initiation and persistence.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.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.

Background The Millennium Cohort Study is a longitudinal cohort study designed in the late 1990s to evaluate how military service may affect long-term health. The purpose of this investigation was to examine characteristics of Millennium Cohort Study participants who responded to the open-ended question, and to identify and investigate the most commonly reported areas of concern. Methods Participants who responded during the 2001-2003 and 2004-2006 questionnaire cycles were included in this study (n = 108,129). To perform these analyses, Latent Semantic Analysis (LSA) was applied to a broad open-ended question asking the participant if there were any additional health concerns. Multivariable logistic regression was performed to examine the adjusted odds of responding to the open-text field, and cluster analysis was executed to understand the major areas of concern for participants providing open-ended responses. Results Participants who provided information in the open-ended text field (n = 27,916), had significantly lower self-reported general health compared with those who did not provide information in the open-ended text field. The bulk of responses concerned a finite number of topics, most notably illness/injury, exposure, and exercise. Conclusion These findings suggest generalized topic areas, as well as identify subgroups who are more likely to provide additional information in their response that may add insight into future epidemiologic and military research.

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.

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.

The objective of this study was to prospectively assess the association between deployment in support of the operations in Iraq and Afghanistan and newly reported lupus and rheumatoid arthritis while also considering the effects of demographic, behavioral, and occupational characteristics. A total of 77,047 (2001–2003) and 31,110 (2004–2006) participants completed the baseline Millennium Cohort questionnaire and were resurveyed approximately every 3 years. Longitudinal analyses were used to assess the adjusted association between deployment to Iraq and Afghanistan with and without combat exposures and newly reported disease. After adjusting, deployment was not significantly associated with newly reported lupus compared with nondeployers. However, compared with nondeployers, deployers with and without combat exposures were significantly less likely to newly report rheumatoid arthritis. Women, non-Hispanic black, and Hispanic participants had a significantly elevated risk for both diseases. Overall, deployment was not associated with an increased risk of newly reported lupus or rheumatoid arthritis.

Background US military engagements have consistently raised concern over the array of health outcomes experienced by service members postdeployment. Exploratory factor analysis has been used in studies of 1991 Gulf War-related illnesses, and may increase understanding of symptoms and health outcomes associated with current military conflicts in Iraq and Afghanistan. The objective of this study was to use exploratory factor analysis to describe the correlations among numerous physical and psychological symptoms in terms of a smaller number of unobserved variables or factors. Methods The Millennium Cohort Study collects extensive self-reported health data from a large, population-based military cohort, providing a unique opportunity to investigate the interrelationships of numerous physical and psychological symptoms among US military personnel. This study used data from the Millennium Cohort Study, a large, population-based military cohort. Exploratory factor analysis was used to examine the covariance structure of symptoms reported by approximately 50,000 cohort members during 2004-2006. Analyses incorporated 89 symptoms, including responses to several validated instruments embedded in the questionnaire. Techniques accommodated the categorical and sometimes incomplete nature of the survey data. Results A 14-factor model accounted for 60 percent of the total variance in symptoms data and included factors related to several physical, psychological, and behavioral constructs. A notable finding was that many factors appeared to load in accordance with symptom co-location within the survey instrument, highlighting the difficulty in disassociating the effects of question content, location, and response format on factor structure. Conclusions This study demonstrates the potential strengths and weaknesses of exploratory factor analysis to heighten understanding of the complex associations among symptoms. Further research is needed to investigate the relationship between factor analytic results and survey structure, as well as to assess the relationship between factor scores and key exposure variables.

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.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.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).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.

Concerns about respiratory conditions have surfaced among persons deployed to Iraq and Afghanistan. Data on 46,077 Millennium Cohort Study participants who completed baseline (July 2001-June 2003) and follow-up (June 2004-February 2006) questionnaires were used to investigate 1) respiratory symptoms (persistent or recurring cough or shortness of breath), 2) chronic bronchitis or emphysema, and 3) asthma. Deployers had a higher rate of newly reported respiratory symptoms than nondeployers (14% vs. 10%), while similar rates of chronic bronchitis or emphysema (1% vs. 1%) and asthma (1% vs. 1%) were observed. Deployment was associated with respiratory symptoms in both Army (adjusted odds ratio = 1.73, 95% confidence interval: 1.57, 1.91) and Marine Corps (adjusted odds ratio = 1.49, 95% confidence interval: 1.06, 2.08) personnel, independently of smoking status. Deployment length was linearly associated with increased symptom reporting in Army personnel (P < 0.0001). Among deployers, elevated odds of symptoms were associated with land-based deployment as compared with sea-based deployment. Although respiratory symptoms were associated with deployment, inconsistency in risk with cumulative exposure time suggests that specific exposures rather than deployment in general are determinants of postdeployment respiratory illness. Significant associations seen with land-based deployment also imply that exposures related to ground combat may be important.

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.

Participant retention is vital to the success of a longitudinal cohort study. Various approaches have been used for retaining participants in longitudinal studies, including maintaining up-to-date contact information. Postcards are sent to Millennium Cohort Study participants each Memorial and Veterans Day to honor their military service, thank them for their continued participation, and prompt them to update their contact information. Descriptive investigations of the Millennium Cohort Study participants who voluntarily updated their contact information online and had a change of address were completed. The percentage of participants who updated their contact information online of the total number of current participants was graphically displayed. Univariate analyses were completed to temporally compare the volume of updated contact information associated with Memorial and Veterans Day postcards. The results show that almost 77% of Cohort members moved between 2001 and 2007. Of these, 12% voluntarily updated their contact information online. Of those who updated their contact information online, 65% updated their contact information at least once within 2 weeks of semiannual postcard contact. Even in times of significant combat deployments, the U.S. military is a highly mobile population. Semiannual appreciatory contact is an effective way to maintain communication with study participants while prompting updates of contact information.

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 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.

Background The prevalence of complementary and alternative medicine (CAM) use has been estimated to be as high as 65% in some populations. However, there has been little objective research into the possible risks or benefits of unmanaged CAM therapies. Methods In this prospective study of active duty US Navy and Marine Corps personnel, the association between self-reported practitioner-assisted or self-administered CAM use and future hospitalization was investigated. Cox regression models were used to examine risk of hospitalization due to any cause over the follow-up period from date of questionnaire submission, until hospitalization, separation from the military, or end of observation period (June 30, 2004), whichever occurred first. Results After adjusting for baseline health, baseline trust and satisfaction with conventional medicine, and demographic characteristics, those who reported self-administering two or more CAM therapies were significantly less likely to be hospitalized for any cause when compared with those who did not self-administer CAM (HR = 0.38; 95% CI = 0.17, 0.86). Use of multiple practitioner-assisted CAM was not associated with a significant decrease or increase of risk for future hospitalization (HR = 1.86; 95 percent confidence interval = 0.96-3.63). Conclusion While there were limitations to these analyses, this investigation utilized an objective measure of health to investigate the potential health effects of CAM therapies and found a modest reduction in the overall risk of hospitalization associated with self-administration of two or more CAM therapies. In contrast, use of practitioner-assisted CAM was not associated with a protective effect.

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.

The stress of military deployment may compound occupational stress experienced in the military and manifest in maladaptive coping behaviors such as cigarette smoking. The current study describes new smoking among never-smokers, smoking recidivism among past smokers, and change in daily smoking among smokers in relation to military deployment.The Millennium Cohort is a 21-year longitudinal study. The current analysis utilized participants (N=48,304) who submitted baseline data (July 2001-June 2003) before the current conflicts in Iraq and Afghanistan and follow-up data (June 2004-January 2006) on health measures. New smoking was identified among baseline never-smokers, smoking recidivism among baseline past smokers, and increased or decreased daily smoking among baseline smokers. Analyses were conducted March 2007-April 2007.Among never-smokers, smoking initiation was identified in 1.3% of nondeployers and 2.3% of deployers. Among past smokers, smoking resumption occurred in 28.7% of nondeployers and 39.4% of those who deployed. Smoking increased 44% among nondeployers and 57% among deployers. Those who deployed and reported combat exposures were at 1.6 times greater odds of initiating smoking among baseline never-smokers (95% CI=1.2, 2.3) and at 1.3 times greater odds of resuming smoking among baseline past smokers when compared to those who did not report combat exposures. Other deployment factors independently associated with postdeployment smoking recidivism included deploying for9 months and deploying multiple times. Among those who smoked at baseline, deployment was not associated with changes in daily amount smoked.Military deployment is associated with smoking initiation and, more strongly, with smoking recidivism, particularly among those with prolonged deployments, multiple deployments, or combat exposures. Prevention programs should focus on the prevention of smoking relapse during or after deployment.