Tomoko I. Hooper

Alcohol Use and Alcohol-Related Problems Before and After Military Combat Deployment

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

Risk factors associated with suicide in current and former US military personnel.

IMPORTANCE 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. OBJECTIVE 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. DESIGN, SETTING, AND PARTICIPANTS 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). MAIN OUTCOMES AND MEASURES Death by suicide captured by the National Death Index and the Department of Defense Medical Mortality Registry. RESULTS 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. CONCLUSIONS AND RELEVANCE 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.

Trajectories of trauma symptoms and resilience in deployed US military service members: prospective cohort study

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

Risk of Diabetes in U.S. Military Service Members in Relation to Combat Deployment and Mental Health

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

The occupational role of women in military service: Validation of occupation and prevalence of exposures in the Millennium Cohort Study

Abstract To better understand the US militarys global peacekeeping and combat operations, which may expose a growing population of American servicewomen 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.

Assessing nonresponse bias at follow-up in a large prospective cohort of relatively young and mobile military service members

BackgroundNonresponse 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.MethodsData 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.ResultsCharacteristics 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.ConclusionsThese findings suggest that prospective analyses from this cohort are not substantially biased by non-response at the first follow-up assessment.

Preinjury Psychiatric Status, Injury Severity, and Postdeployment Posttraumatic Stress Disorder

CONTEXT 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. OBJECTIVE To prospectively assess the relationship of predeployment psychiatric status and injury severity with postdeployment PTSD. DESIGN Prospective, longitudinal study. SETTING United States military personnel deployed in support of the conflicts in Iraq and Afghanistan. PARTICIPANTS 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. MAIN OUTCOME MEASURES A positive screening result using the PTSD Checklist-Civilian Version. RESULTS 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. CONCLUSIONS 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.

Sleep Characteristics, Mental Health, and Diabetes Risk: A prospective study of U.S. military service members in the Millennium Cohort Study

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 <6 h, and sleep apnea. Participants reporting incident diabetes were also significantly older, of nonwhite race, of higher BMI, less likely to have been deployed, and more likely to have reported baseline symptoms of panic, anxiety, posttraumatic stress disorder, and depression. After adjusting for covariates, trouble sleeping (odds ratio 1.21 [95% CI 1.03–1.42]) and sleep apnea (1.78 [1.39–2.28]) were significantly and independently related to incident diabetes. CONCLUSIONS Trouble sleeping and sleep apnea predict diabetes risk independent of mental health conditions and other diabetes risk factors.

Aeromedical Evacuations from Operation Iraqi Freedom: A Descriptive Study

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

Health impact of US military service in a large population-based military cohort: findings of the Millennium Cohort Study, 2001-2008

BackgroundCombat-intense, lengthy, and multiple deployments in Iraq and Afghanistan have characterized the new millennium. The US militarys 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.MethodsThe 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.ResultsOver 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.ConclusionThe 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.