Bidirectional Associations between Probable Eating Disorders and Mental Health Conditions Among Military Service Members and Veterans.

Although prior research has examined the prevalence of eating disorders (EDs) such as binge eating disorder (BED) and bulimia nervosa (BN) among military personnel, less is known regarding temporal associations between EDs and other mental health conditions. Using longitudinal data from 179,694 service members and veterans from the Millennium Cohort Study, temporal associations between EDs (BN, BED) and mental health conditions (posttraumatic stress disorder, anxiety, depression, and problem drinking) were investigated using a cross-lagged panel model approach. Results indicated consistent bidirectional associations between most mental health conditions and EDs; however, the magnitude of these cross-lagged associations varied across BN and BED. Cross-lagged effects of mental health conditions on subsequent BED were significantly stronger than BED to mental health condition cross-lagged effects. In contrast, cross-lagged effects of BN on subsequent mental health conditions were stronger than mental health conditions to BN. Preventive screening for those at risk for BN may have a stronger impact on mitigating downstream mental health conditions, while interventions among those with mental health conditions may play a greater role in eliminating maladaptive coping strategies including binge eating. Study findings underscore the importance of early detection of mental health conditions and EDs to maximize readiness among service members.

Prevalence and Risk Factors for the Development of Bulimia Nervosa and Binge Eating Disorder in a Large U.S. Military Cohort.

While bulimia nervosa (BN) and binge eating disorder (BED) are prevalent in military populations, an understanding of risk and protective factors is limited by a lack of longitudinal population-based epidemiological research. This study examined the prevalence of BN and BED among active duty service members and identified military and psychosocial factors associated with their development. Millennium Cohort Study participants were followed for up to 15 years and prevalence was ascertained using survey and electronic medical record data. Longitudinal multivariable logistic regression models evaluated risk factors associated with the development of bulimia nervosa (n=96,245) or binge eating disorder (n=113,733). Weighted prevalence estimates from survey data (range, 0.80%-4.80%) were higher than those from medical records (0.04%-0.14%). Military factors significantly associated with increased risk for BN and BED included active duty component (vs Reserve/Guard); serving in the Army, Marines, or Navy/Coast Guard (vs Air Force); and combat deployment (vs deployment without combat). Associated psychosocial factors included lack of social support, experiencing at least one life stressor, and screening positive for posttraumatic stress disorder or problem drinking. Findings highlight the critical need for disordered eating screening and prevention efforts that bolster coping skills, which can ultimately improve service member functioning and readiness.

Racial, Ethnic, and Sex Differences in Eating Disorder Onset Among U.S. Military Service Members.

Bulimia nervosa (BN) and binge eating disorder (BED) are the most prevalent eating disorders (EDs) among military personnel. Although sex differences are noted in ED prevalence in military and civilian samples, mixed findings have emerged when evaluating racial and ethnic differences. The present study examined independent associations and interactions between sex, race, ethnicity, and probable BED and BN onset. The sample included 91,413 and 96,245 service members from the Millennium Cohort Study for BED and BN analyses, respectively. Up to four datapoints (from 2001-2013) were used to conduct longitudinal complementary log-log regression analyses, as participants were followed until the outcome occurred or until study completion. BN was more likely among women than men, and no sex difference emerged for BED onset. BN was more likely among Hispanic/Latinx, Multiracial, Black, and Asian/Pacific Islander (API) while BED was less likely among Black and API versus non-Hispanic/Latinx White (NHW) service members. Interactions revealed greater likelihood of BN in Hispanic/Latinx service members was driven by men. Additional efforts are needed amongst racially and ethnically diverse groups in preventing and detecting EDs in military personnel. Future intersectionality research could elucidate systemic inequities and other contributing factors to ED onset to inform prevention and treatment efforts.

Risk and Protective Factors of Probable Binge Eating Disorder in US Military Spouses: Findings From the Millennium Cohort Family Study.

Binge eating disorder (BED) is a public health concern that has received little research attention in military families. Further research is needed to identify risk and protective factors to inform intervention and prevention efforts. This longitudinal study examined predictors of probable BED in a sample of U.S. military spouses (N = 5,269). Data were derived from the Millennium Cohort Family Study, which included baseline assessments of risk and protective factors and a follow-up assessment of probable BED approximately 3 years later. Results of a multivariable logistic regression model indicated that spouses with probable posttraumatic stress disorder, adverse childhood experiences, or who were former smokers had increased risk of probable BED at follow-up. Spouses whose service member had a deployment with combat exposure, or had not deployed, had higher risk of probable BED than spouses whose service member deployed without combat exposure. Age >34 years was the only protective factor to emerge as significant in the adjusted model. Results highlighted the need for interventions to improve psychoeducation and coping skills in military spouses, which may mitigate BED symptoms stemming from military-related stressors (e.g., combat deployment) or prior trauma, especially once maladaptive coping mechanisms (e.g., smoking) have ceased.

Sleep health among US Navy afloat versus ashore personnel in the Millennium Cohort Study.

Despite emerging public concern regarding the sleep health of military personnel over the past two decades, there remains a dearth of research examining sleep health among naval personnel assigned to sea duty. This study examined sleep metrics (e.g. fatigue, short sleep duration) and mental (e.g. posttraumatic stress disorder, depression) and physical health (e.g. type 2 diabetes, bodily pain) outcomes among naval personnel with recent sea duty (i.e. afloat) compared with naval personnel with recent shore duty (i.e. ashore). Prevalence ratios and mean differences for all outcomes were estimated and adjusted for demographic and military variables, and subsequently stratified by obesity. Sleep metrics were similar between afloat and ashore sailors except for short sleep duration, while sailors with recent shore duty had poorer physical health compared with those with recent sea duty. Stratified analyses suggested naval personnel with obesity had a higher proportion of nearly all adverse sleep-related health outcomes than those without obesity. Among participants without obesity, afloat personnel were more likely to report very short sleep (≤ 5 hours) and fewer hours of average nightly sleep, but were less likely to report physical health outcomes compared with ashore personnel. These findings suggest potential differences in sleep metrics and sleep-related health outcomes between afloat and ashore naval personnel. Additional research examining sleep outcomes using more objective measures is required to further investigate these findings, which may inform strategies to foster consolidated sleep despite environmental and occupational challenges in order to maintain high-performing naval personnel.

Military service experiences and reasons for service separation among lesbian, gay, and bisexual individuals in a large military cohort.

BACKGROUND: The well-being of lesbian, gay, and bisexual (LGB) individuals is a topic of increasing concern within the military where significant institutional barriers, targeted aggression, and differential organizational policies such as "Don't Ask Don't Tell" have historically contributed to experiences of exclusion and discrimination. However, limited research has examined specific military and post-separation experiences among LGB service members and veterans. The goal of this study was to examine differences in military and service separation experiences by sexual orientation among a large representative sample of United States service members and veterans. METHODS: Survey data from the 2016 Millennium Cohort Study follow-up questionnaire were used to assess sexual orientation and multiple outcomes of interest: military experiences (morale, feelings about the military, missed workdays) and service separation experiences (reasons for separation, post-separation employment). The associations between sexual orientation (LGB versus heterosexual) and each of these outcomes were evaluated in a series of adjusted logistic regression models, stratified by sex when interactions were observed. RESULTS: Of the 99,599 participants, 3.4% identified as LGB. In adjusted models, LGB service members had significantly higher odds than heterosexual service members of feeling: unimpressed by the quality of unit leadership, unsupported by the military, and negative about the military overall. Bisexual women were more likely than heterosexual women to feel less unit camaraderie; both gay and bisexual men felt less camaraderie than heterosexual men. LGB veterans were more likely than heterosexual peers of the same sex to separate from service due to unplanned administrative reasons. Compared to heterosexual women, lesbian and bisexual women were more likely to separate from service due to dissatisfaction with promotions/pay and disability/medical reasons, while bisexual women specifically separated due to dissatisfaction with leadership and incompatibility with the military. Gay and bisexual men also reported separating due to incompatibility with the military, but only bisexual men were more likely to report separating due to disability/medical reasons compared to heterosexual men. CONCLUSIONS: Less positive military- and separation-specific experiences disproportionately affected LGB service members in this study. Promoting inclusion and increasing support for LGB service members may improve satisfaction with military service and retention.

Magnitude of problematic anger and its predictors in the Millennium Cohort.

BACKGROUND: Problematic anger is intense anger associated with elevated generalized distress and that interferes with functioning. It also confers a heightened risk for the development of mental health problems. In military personnel and veterans, previous studies examining problematic anger have been constrained by sample size, cross-sectional data, and measurement limitations. METHODS: The current study used Millennium Cohort survey data (N = 90,266) from two time points (2013 and 2016 surveys) to assess the association of baseline demographics, military factors, mental health, positive perspective, and self-mastery, with subsequent problematic anger. RESULTS: Overall, 17.3% of respondents reported problematic anger. In the fully adjusted logistic regression model, greater risk of problematic anger was predicted by certain demographic characteristics as well as childhood trauma and financial problems. Service members who were in the Army or Marines, active duty (vs. reserves/national guard), and previously deployed with high levels of combat had increased risk for problematic anger. Veterans were also more likely to report problematic anger than currently serving personnel. Mental health predictors included posttraumatic stress disorder (PTSD), major depressive disorder (MDD), and comorbid PTSD/MDD. Higher levels of positive perspective and self-mastery were associated with decreased risk of problematic anger. CONCLUSION: Not only did 1 in 6 respondents report problematic anger, but risk factors were significant even after adjusting for PTSD and MDD, suggesting that problematic anger is more than an expression of these mental health problems. Results identify potential targets of early intervention and clinical treatment for addressing problematic anger in the military and veteran context.

Longitudinal Investigation of Smoking Initiation and Relapse Among Younger and Older US Military Personnel.

OBJECTIVES: We examined whether military service, including deployment and combat experience, were related to smoking initiation and relapse. METHODS: We included older (panel 1) and younger (panel 2) participants in the Millennium Cohort Study. Never smokers were followed for 3 to 6 years for smoking initiation, and former smokers were followed for relapse. Complementary log-log regression models estimated the relative risk (RR) of initiation and relapse by military exposure while adjusting for demographic, health, and lifestyle factors. RESULTS: Deployment with combat experience predicted higher initiation rate (panel 1: RR = 1.44; 95% confidence interval [CI] = 1.28, 1.62; panel 2: RR = 1.26; 95% CI = 1.04, 1.54) and relapse rate (panel 1 only: RR = 1.48; 95% CI = 1.36, 1.62). Depending on the panel, previous mental health disorders, life stressors, and other military and nonmilitary characteristics independently predicted initiation and relapse. CONCLUSIONS: Deployment with combat experience and previous mental disorder may identify military service members in need of intervention to prevent smoking initiation and relapse.

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.

Gender differences of postdeployment post-traumatic stress disorder among service members and veterans of the Iraq and Afghanistan conflicts.

Despite the marked expansion of roles for women in the US military over the last decade, whether differences by gender exist in regard to the development of mental health conditions postdeployment is unclear. This comprehensive review of the literature (2001-2012) examined whether US servicewomen were more likely than men to experience post-traumatic stress disorder (PTSD) after returning from deployments to the Iraq and Afghanistan conflicts. Findings from 18 studies from 8 unique study populations were reviewed. Seven studies found that women had a higher risk for screening positive for PTSD compared with men, including prospectively designed studies that evaluated new-onset PTSD among members from all service branches. Although results from studies with Veterans Affairs samples found women at decreased risk in 4 analyses, these studies used the same source databases, were conducted in treatment-seeking populations, and were mostly unable to account for combat experience. Seven studies detected no differences by gender. In summary, women appeared to have a moderately higher risk for postdeployment PTSD, although there was a lack of consensus among the studies, and even those with the most rigorous methods were not designed specifically to evaluate potential gender differences. Given the limitations of the published literature, further research should use longitudinal study designs and comprehensive evaluations of deployment experiences while adjusting for predeployment factors to confirm that gender differences exist with regard to postdeployment PTSD.

The impact of deployment experience and prior healthcare utilization on enrollment in a large military cohort study.

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.

The impact of prior deployment experience on civilian employment after military service.

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

Contribution of post-trauma insomnia to depression and posttraumatic stress disorder in women service members: findings from the Millennium Cohort Study.

STUDY OBJECTIVES: We examined whether women service members and veterans who reported recent combat and/or sexual trauma experiences had a greater risk of insomnia compared with women who did not report these recent experiences, and whether insomnia would be associated with a greater risk of mental health outcomes. METHODS: We analyzed two waves of survey data (2011-2013, Time 1 [T1] and 2014-2016, Time 2 [T2]) from 26 443 current and former women service members from the Millennium Cohort Study. We assessed recent traumas in the past 3 years, and probable insomnia at T1 and probable post-traumatic stress disorder (PTSD) and depression at T2. A longitudinal mediation model was used to quantify separate indirect effects of recent traumas on mental health outcomes through probable insomnia. RESULTS: Women who had experienced recent sexual assault (odds ratio [OR] = 1.68; 95% CI = 1.24-2.10), sexual harassment (OR = 1.22; 95% CI = 1.05-1.41), and combat (OR = 1.34; 95% CI = 1.20-1.49) at T1 had a greater risk of probable insomnia at T1 compared with women who had not recently experienced these events. Probable insomnia at T1, in turn, was associated with probable depression (OR = 2.66; 95% CI = 2.31-3.06) and PTSD (OR = 2.57; 95% CI = 2.27-2.90) at T2. Recent combat experience did not moderate the associations of recent sexual trauma with insomnia or mental health outcomes. CONCLUSIONS: Insomnia contributes to the risk of subsequent mental health conditions following trauma. The diagnosis and treatment of post-trauma insomnia should be prioritized to mitigate the development of posttraumatic mental health conditions.

Individual and Military Factors That Modify the Association Between Recent Sexual Trauma and Health Outcomes Among U.S. Service Members and Veterans.

Sexual trauma (ST), which includes both sexual harassment and sexual assault, is associated with a variety of adverse mental and physical health outcomes in military and civilian populations. However, little is known about whether certain individual or military attributes or prior experiences may modify the relationship between recent ST and mental or physical health outcomes. Data from a longitudinal cohort study of current and former military members were used to examine whether individual and military factors modify the association between recent ST and health outcomes (posttraumatic stress disorder, depression, multiple somatic symptoms, and insomnia). Results indicated that demographic (sex, sexual orientation, race/ethnicity) and military factors (service branch, service component, military separation) generally did not modify the main effect of ST on the outcomes examined. On the other hand, factors known to be protective (spirituality, social support) and risk factors (childhood trauma, combat deployment, and mental health status) did modify the effect of ST on multiple outcomes examined; notably, protective effects were diminished among those who experienced recent ST. Protective factors were associated with the lowest risk of adverse outcomes among those with no ST, while risk reduction was less among survivors of ST. Diminished impacts also were found for cumulative risk factors, with the influence of multiple individual risk factors associated with increased risk but in a subadditive manner. We conclude that the effect of recent ST on the outcomes examined was persistent in the presence of potential protective factors, but that it may be impacted by ceiling effects in combination with other risk factors.

Partner Effects: Analyzing Service Member and Spouse Drinking Over Time.

INTRODUCTION: Excessive alcohol use is a significant problem in the military. Although there is a growing emphasis on family-centered alcohol prevention approaches, little is known about the interplay between partners' drinking behaviors. This study examines how service members and their spouses influence each other's drinking behavior over time and explores the complex individual, interpersonal, and organizational factors that may contribute to alcohol use. METHODS: A sample of 3,200 couples from the Millennium Cohort Family Study was surveyed at baseline (2011-2013) and follow-up (2014-2016). The research team estimated how much partners' drinking behaviors influenced one another from baseline to follow-up using a longitudinal structural equation modeling approach. Data analyses were conducted in 2021 and 2022. RESULTS: Drinking patterns converged between spouses from baseline to follow-up. Participants' own baseline drinking had a small but significant effect on changes in their partners' drinking from baseline to follow-up. Results from a Monte Carlo simulation showed that the longitudinal model could reliably estimate this partner effect in the presence of several potential sources of bias, including partner selection. The model also identified several common risk and protective factors for drinking shared by both service members and their spouses. CONCLUSIONS: Findings suggest that changing the drinking habits of one spouse could lead to a change in the drinking habits of the other, which supports family-centered alcohol prevention approaches in the military. Dual-military couples especially may benefit from targeted interventions because they face a higher risk of unhealthy alcohol consumption.

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.

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.

Posttraumatic stress disorder and depression among U.S. military health care professionals deployed in support of operations in Iraq and Afghanistan.

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

Association of deployment with maintenance of healthy weight among active duty service members in the Millennium Cohort Study.

Objective: Understanding body size in relation to deployment readiness can inform Department of Defense fitness policies. This study examined longitudinal associations between deployment and changes in body mass index (BMI) among active duty service members. Methods: Service branch-specific changes in BMI post-deployment were examined using logistic regression models among active duty Millennium Cohort Study participants without obesity at baseline (n = 22,995). BMI was categorized using self-reported height and weight as healthy weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), and obese (≥30 kg/m2). Number of deployments between baseline and follow-up and initial deployment lengths (in months, using service branch-specific deployment times) were examined. Results: Among the pooled population and specifically Army and Marine Corps service members without obesity, those with longer deployments were significantly less likely to maintain a non-obese BMI than those deploying for shorter lengths. Each additional deployment increased the likelihood of maintaining a non-obese BMI post-deployment for personnel in the Army, Marine Corps, and within the pooled population. Conclusions: Multiple deployments may support healthy weight maintenance; longer deployments may adversely impact weight maintenance. Future research should determine modifiable behaviors related to weight gain post-deployment to inform fitness policies designed to optimize service member readiness and deployability.