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PURPOSE This study evaluated risk factors predicting unplanned 30-day acute service utilization among adults subsequent to hospitalization for a new diagnosis of leukemia, lymphoma, or myeloma. This study explored the prevalence of medical complications (aligned with OP-35 measure specifications from the Centers for Medicare & Medicaid Services [CMS] Hospital Outpatient Quality Reporting Program) and the potential impact of psychosocial factors on unplanned acute care utilization. METHODS This study included 933 unique patients admitted to three acute care inpatient facilities within a nonprofit community-based health care system in southern California from 2012 to 2017. Integrated comprehensive data elements from electronic medical records and facility oncology registries were leveraged for univariate statistics, predictive models constructed using multivariable logistic regression, and further exploratory data mining, with predictive accuracy of the models measured with c-statistics. RESULTS The mean age of study participants was 65 years, and 55.1% were male. Specific diagnoses were lymphoma (48.7%), leukemia (35.2%), myeloma (14.0%), and mixed types (2.1%). Approximately one fifth of patients received unplanned acute care services within 30 days postdischarge, and over half of these patients presented with one or more symptoms associated with the CMS medical complication measure. The predictive models, with c-statistics ranging from 0.7 and above for each type of hematologic malignancy, indicated good predictive qualities with the impact of psychosocial functioning on the use of acute care services ( P values < .05), including lack of consult for social work during initial admission (lymphoma or myeloma), history of counseling or use of psychotropic medications (lymphoma), and past substance use (myeloma). CONCLUSION This study provides insights into patient-related factors that may inform a proactive approach to improve health outcomes, such as enhanced care transition, monitoring, and support interventions.

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

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

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

To investigate respiratory illnesses and potential open-air burn pit exposure among Millennium Cohort participants who deployed to Iraq or Afghanistan.Using multivariable logistic regression, newly reported chronic bronchitis or emphysema, newly reported asthma, and self-reported respiratory symptoms and possible burn pit exposure within 2, 3, or 5 miles were examined among Army and Air Force deployers surveyed in 2004 to 2006 and 2007 to 2008 (n = 22,844).Burn pit exposure within 3 or 5 miles was not associated with respiratory outcomes after statistical adjustment. Increased symptom reporting was observed among Air Force deployers located within 2 miles of Joint Base Balad; however, this finding was marginally significant with no evidence of trend.In general, these findings do not support an elevated risk for respiratory outcomes among personnel deployed within proximity of documented burn pits in Iraq.

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.

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.

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.

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.

In December 2002, the US Government implemented policy to immunize health workers, first responders, and military personnel against smallpox in preparation for a possible bioterrorist attack. Self-reported vaccination data are commonly used in epidemiologic research and may be used to determine vaccination status in a public health emergency. To establish a measure of reliability, the agreement between self-reported smallpox vaccination and electronic vaccination records was examined using data from the Millennium Cohort Study. Descriptive measures and a kappa statistic were calculated for data from 54,066 Millennium Cohort Study participants. Multivariable modeling adjusting for potential confounders was used to investigate vaccination agreement status and health metrics, as measured by the Short Form 36-Item Health Survey for Veterans (SF-36V) and hospitalization data. Substantial agreement (kappa =0.62) was found between self-report and electronic recording of smallpox vaccination. Of all participants with an electronic record of smallpox vaccination, 90% self-reported being vaccinated; and of all participants with no electronic record of vaccination, 82% self-reported not receiving a vaccination. There was no significant difference in hospitalization experience prior to questionnaire completion between vaccinated and unvaccinated participants. While overall scores on the SF-36V suggested a healthy population, participants whose self-reported vaccination status did not match electronic records had slightly lower adjusted mean scores for some scales. These results indicate strong reliability in self-reported smallpox vaccination and also suggest that discordant reporting of smallpox vaccination is not associated with substantial differences in health among Millennium Cohort participants.

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.

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

Background 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.

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.

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.

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

Background Often in survey research, subsets of the population invited to complete the survey do not respond in a timely manner and valuable resources are expended in recontact efforts. Various methods of improving response have been offered, such as reducing questionnaire length, offering incentives, and utilizing reminders; however, these methods can be costly. Utilizing characteristics of early responders (refusal or consent) in enrollment and recontact efforts may be a unique and cost-effective approach for improving the quality of epidemiologic research. Methods To better understand early responders of any kind, we compared the characteristics of individuals who explicitly refused, consented, or did not respond within 2 months from the start of enrollment into a large cohort study of US military personnel. A multivariate polychotomous logistic regression model was used to estimate the effect of each covariate on the odds of early refusal and on the odds of early consent versus late/non-response, while simultaneously adjusting for all other variables in the model. Results From regression analyses, we found many similarities between early refusers and early consenters. Factors associated with both early refusal and early consent included older age, higher education, White race/ethnicity, Reserve/Guard affiliation, and certain information technology and support occupations. Conclusion These data suggest that early refusers may differ from late/non-responders, and that certain characteristics are associated with both early refusal and early consent to participate. Structured recruitment efforts that utilize these differences may achieve early response, thereby reducing mail costs and the use of valuable resources in subsequent contact efforts.

Background Recently, numerous studies have revealed an increase in complementary and alternative medicine (CAM) use in US civilian populations. In contrast, few studies have examined CAM use within military populations, which have ready access to conventional medicine. Currently, the prevalence and impact of CAM use in US military populations remains unknown. Methods To investigate CAM use in US Navy and Marine Corps personnel, the authors surveyed a stratified random sample of 5,000 active duty and Reserve/National Guard members between December 2000 and July 2002. Chi-square tests and multivariable logistic regression were used to assess univariate associations and adjusted odds of CAM use in this population. Results and discussion Of 3,683 service members contacted, 1,446 (39.3%) returned a questionnaire and 1,305 gave complete demographic and survey data suitable for study. Among respondents, more than 37% reported using at least one CAM therapy during the past year. Herbal therapies were among the most commonly reported (15.9%). Most respondents (69.8%) reported their health as being very good or excellent. Modeling revealed that CAM use was most common among personnel who were women, white, and officers. Higher levels of recent physical pain and lower levels of satisfaction with conventional medical care were significantly associated with increased odds of reporting CAM use. Conclusion These data suggest that CAM use is prevalent in the US military and consistent with patterns in other US civilian populations. Because there is much to be learned about CAM use along with allopathic therapy, US military medical professionals should record CAM therapies when collecting medical history data.

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 lon...

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.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.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.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.

An outbreak of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin infections was observed in a population of U.S. military trainees in the summer of 2002. A questionnaire was developed and administered to 206 trainees, 22 of whom had MRSA infections. Factors associated with infection were described by multivariable logistic regression modeling and included having a roommate in training with a prior skin infection (odds ratio [OR] = 3.44) or having a family member or friend who worked in a health care setting (OR = 2.79). Previous antibiotic use, hospitalization, or health problems were not associated with MRSA infection. This outbreak of MRSA skin infections in an otherwise-healthy, well-defined, military population provided an opportunity to describe risk factors for CA-MRSA which may help focus prevention efforts in this and other communities.

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

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

Background Longitudinal cohort studies are highly valued in epidemiologic research for their ability to establish exposure-disease associations through known temporal sequences. A major challenge in cohort studies is recruiting individuals representative of the targeted sample population to ensure the generalizability of the study’s findings. Methods We evaluated nearly 350,000 invited subjects (from 2004-2008) of the Millennium Cohort Study, a prospective cohort study of the health of US military personnel, for factors prior to invitation associated with study enrollment. Multivariable logistic regression was utilized, adjusting for demographic and other confounders, to determine the associations between both deployment experience and prior healthcare utilization with enrollment into the study. Results Study enrollment was significantly greater among those who deployed prior to and/or during the enrollment cycles or had at least one outpatient visit in the 12 months prior to invitation. Mental disorders and hospitalization for more than two days within the past year were associated with reduced odds of enrollment. Conclusions These findings suggest differential enrollment by deployment experience and health status, and may help guide recruitment efforts in future studies.

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.