Cigarette smoking patterns among U.S. military service members before and after separation from the military.

U.S. military Service members have consistently smoked more than the general population and the prevalence of smoking is even higher among U.S. veterans. Our study examined cigarette smoking patterns among Service members before and after military separation to better understand the disproportionate rate of smoking among veterans. Data from the Millennium Cohort Study were used. All study participants were in the military at baseline and some transitioned from the military to civilian life during the observation period. We investigated any impact of military separation on smoking, as well as other potential risk factors for smoking. Overall, we observed higher smoking prevalence among veterans than Service members. Additionally, we found that Service members smoked more while approaching their separation from the military. Longitudinal analysis revealed military separation was not a risk factor for smoking, as we had hypothesized. Baseline smoking was the most influential predictor of current smoking status. Other significant factors included alcohol consumption, life stressors, and mental health conditions, among others. Military separation was not a risk factor for smoking. However, Service members in the process of transitioning out of the military, as well as high alcohol consumers and Service members with mental health conditions, may be at higher risk of smoking. Including smoking prevention/cessation programs in pre-separation counseling sessions and developing smoking screening and cessation programs targeting specific high-risk subgroups may reduce smoking among Service members and veterans.

Sexual Harassment, Sexual Assault, and Physical Activity Among U.S. Military Service Members in the Millennium Cohort Study.

Sexual harassment (SH) and sexual assault (SA) continue to be a focus of prevention efforts in the U.S. military because of the prevalence and potential to affect the health and readiness of service members. Limited research exists on the association of SH and SA with coping behaviors, such as physical activity, within the military. Data including self-reported SA, SH, and physical activity were obtained from the Millennium Cohort Study, a longitudinal cohort study designed to examine the impact of military service on the health and well-being of service members. A hierarchical regression approach was applied to examine the association between SH or SA and subsequent physical activity levels. Hierarchical regression showed that, among those self-reporting recent SA, the odds of medium-high (300-449 min/week) and high physical activity levels (≥450 min/week) were significantly increased. Although the magnitude of these associations was attenuated with an increasing amount of adjustment, the odds of high physical activity levels remained statistically significant in the fully adjusted model (medium-high: odds ratio [OR] = 1.72, 95% confidence interval [CI] = [1.08, 2.73]; high: OR = 1.58, 95% CI = [1.02, 2.44]). We observed statistically significant negative associations between recent SH and medium-high physical activity levels in adjusted models (OR = 0.70, 95% CI = [0.54, 0.91]). The current results demonstrate that SA is generally associated with increased levels of physical activity among military service members. Analyzing the relationship between sexual trauma and physical activity is valuable because of the high prevalence of SH and SA in the military, long-term health implications including physical and emotional well-being, and potential impact on military readiness.

Smoking Among U.S. Service Members Following Transition From Military to Veteran Status.

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

Comparing self-reported physical activity and sedentary time to objective fitness measures in a military cohort.

OBJECTIVES: Regular vigorous physical activity (PA) and high levels of physical fitness (PF) confer health benefits. Conversely, sedentary time is a risk factor for chronic illness, independent of PA. We evaluated associations between self-reported PA, sedentary time, and objective PF measures in military Service members. DESIGN: Cross-sectional study including 10,105 Air Force Millennium Cohort participants with a valid physical fitness assessment (PFA). METHODS: Linear regression assessed associations between self-report PA, screen time, and usual activity and abdominal circumference (AC) and VO2 max; logistic regression was used for PFA failure. We stratified by age and sex. RESULTS: Men who self-reported high versus low levels of PA had greater AC (19-29 years: ß=0.23in., 95% CI 0.07, 0.39; 30-39 years: ß=0.45in., 95% CI 0.17, 0.72). High versus low self-reported PA was also associated with greater VO2Max (ß=:0.81-1.41mL/kg/min). Self-reported strength training for ≥2days/week was associated with greater VO2Max in 19-29year old men (ß=0.84mL/kg/min, 95% CI 0.09, 0.60) and 30-39year old women (ß=0.74mL/kg/min, 95% CI 0.02, 1.46). For younger men and women,<2h of screen time/day was associated with greater VO2Max (Males 19-29years: ß=0.23mL/kg/min, 95% CI 0.44, 1.26; Females 19-29years: ß=0.83mL/kg/min, 95% CI 0.25, 1.42). PA was not associated with PFA failure, while screen time was (Males OR: 0.32-0.65, 95% CI 0.17-0.92, p<0.001-0.016). CONCLUSIONS: Self-reported PA and screen time were associated with some objective PF measures, including VO2Max and AC. However, screen time alone was associated with PFA failure.

Longitudinal Assessment of Self-Reported Recent Back Pain and Combat Deployment in the Millennium Cohort Study.

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.

The Epidemiology of Irritable Bowel Syndrome in the US Military: Findings from the Millennium Cohort Study.

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

Hearing loss associated with US military combat deployment.

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

Chronic multisymptom illness: a comparison of Iraq and Afghanistan deployers with veterans of the 1991 Gulf War.

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.

Deployment-related depression screening, 2001-2008: comparing clinical versus research surveys.

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

Relative cost-effectiveness of a norovirus vaccine in the deployed military setting compared to a vaccine against Campylobacter sp., ETEC, and Shigella sp.

Norovirus (NoV) has been identified as a significant cause of acute gastrointestinal illness among deployed military troops. We conducted a cost-effectiveness analysis for the use of a NoV vaccine in the military using a previously developed model that evaluated vaccines for ETEC, Campylobacter, and Shigella for prevention of non-outbreak associated travelers' diarrhea. Under conservative assumptions, acquisition of a NoV vaccine by the Department of Defense is estimated to result in a cost-effectiveness ratio per duty day lost to illness (CERDDL) of $1344 compared to a CERDDL of $776, $800, and $1275 for ETEC, Campylobacter sp., and Shigella sp., respectively compared to current management strategies. The absolute value of avoiding a duty day lost is likely to vary under different scenarios, and further study is needed to evaluate how improved diagnostics and prevention of outbreaks may impact the relative value of this vaccine. Overall, this study demonstrates the utility of a previously established evidence-based decision tool for prioritization of vaccine acquisition in an important target population.

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.

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.

Predeployment Sleep Duration and Insomnia Symptoms as Risk Factors for New-Onset Mental Health Disorders Following Military Deployment.

STUDY OBJECTIVES: To evaluate predeployment sleep duration and insomnia symptoms in relation to the development of mental health symptoms. DESIGN: Longitudinal cohort study. SETTING: The Millennium Cohort Study survey is administered via a secure website or US mail. PARTICIPANTS: Data were from 15,204 participants who completed their first deployment between the submissions of 2 consecutive Millennium Cohort questionnaires (2001-2008). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Using self-reported data from the Millennium Cohort Study we evaluated the association of predeployment sleep duration and insomnia symptoms on the development of new-onset mental disorders among deployers. Multivariable logistic regression was used to estimate the odds of developing posttraumatic stress disorder (PTSD), depression, and anxiety, while adjusting for relevant covariates including combat-related trauma. The study outcomes were assessed using validated instruments, including the PTSD checklist-civilian version, and the PRIME-MD Patient Health Questionnaire. We identified 522 people with new-onset PTSD, 151 with anxiety, and 303 with depression following deployment. In adjusted models, combat-related trauma and predeployment insomnia symptoms were significantly associated with higher odds of developing posttraumatic stress disorder, depression, and anxiety postdeployment. CONCLUSIONS: Sleep characteristics, especially insomnia symptoms, are related to the development of mental disorders following military deployments. Assessment of insomnia symptoms predeployment may help to better identify those at highest risk for subsequent adverse mental health outcomes. CITATION: Gehrman P; Seelig AD; Jacobson IG; Boyko EJ; Hooper TI; Gackstetter GD; Ulmer CS; Smith TC; for the Millennium Cohort Study Team. Predeployment sleep duration and insomnia symptoms as risk factors for new-onset mental health disorders following military deployment. SLEEP 2013;36(7):1009-1018.

Is military deployment a risk factor for maternal depression?

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Prospective evaluation of mental health and deployment experience among women in the US military.

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.

Prospective assessment of chronic multisymptom illness reporting possibly associated with open-air burn pit smoke exposure in Iraq.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: There was no increase in CMI symptom reporting in those deployed to three selected bases with documented burn pits compared with other deployers.

A comparison of mental health outcomes in persons entering U.S. military service before and after September 11, 2001.

It has been hypothesized that those who entered military service in the pre-September 11, 2001 era might have expectations incongruent with their subsequent experiences, increasing the risk for posttraumatic stress disorder (PTSD) or other mental disorders. A subset of Millennium Cohort Study participants who joined the military during 1995-1999 was selected and compared with a subset of members who joined the military in 2002 or later. Outcomes included new-onset symptoms of PTSD, depression, panic/anxiety, and alcohol-related problems. Multivariable methods adjusted for differences in demographic and military characteristics. More than 11,000 cohort members were included in the analyses. Those who entered service in the pre-September 11 era had lower odds of new-onset PTSD symptoms (odds ratio [OR] 0.74, 95% CI [0.59, 0.93]) compared with the post-September 11 cohort. There were no statistically significant differences in rates of new-onset symptoms of depression, panic/anxiety, or alcohol-related problems between the groups. The cohort who entered military service in the pre-September 11 era did not experience higher rates of new-onset mental health challenges compared with the cohort who entered service after September 11, 2001. Findings support the concept that the experience of war, and resulting psychological morbidity, is not a function of incongruent expectations.

Trajectories of trauma symptoms and resilience in deployed U.S. 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.

Headache disorders in the millennium cohort: epidemiology and relations with combat deployment.

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