Millennium Cohort: enrollment begins a 21-year contribution to understanding the impact of military service

Utilizing machine learning to predict participant response to follow-up health surveys in the Millennium Cohort Study

The Millennium Cohort Study is a longitudinal study which collects self-reported data from surveys to examine the long-term effects of military service. Participant nonresponse to follow-up surveys presents a potential threat to the validity and generalizability of study findings. In recent years, predictive analytics has emerged as a promising tool to identify predictors of nonresponse. Here, we develop a high-skill classifier using machine learning techniques to predict participant response to follow-up surveys of the Millennium Cohort Study. Six supervised algorithms were employed to predict response to the 2021 follow-up survey. Using latent class analysis (LCA), we classified participants based on historical survey response and compared prediction performance with and without this variable. Feature analysis was subsequently conducted on the best-performing model. Including the LCA variable in the machine learning analysis, all six algorithms performed comparably. Without the LCA variable, random forest outperformed the benchmark regression model, however overall prediction performance decreased. Feature analysis showed the LCA variable as the most important predictor. Our findings highlight the importance of historical response to improve prediction performance of participant response to follow-up surveys. Machine learning algorithms can be especially valuable when historical data are not available. Implementing these methods in longitudinal studies can enhance outreach efforts by strategically targeting participants, ultimately boosting survey response rates and mitigating nonresponse.

Factors influencing postdeployment reintegration adjustment for U.S. service members and their spouses by spouse gender

Research on spouses' adjustment after military deployment has focused primarily on female spouses of male service members; little is known about how adjustment differs by gender. We used Walsh's family resilience framework to examine communication, belief system, organizational factors, and other stressors, likely associated with postdeployment adjustment. Using Millennium Cohort Family Study data, logistic regressions assessed risk and protective factors on spouses' and service members' time to adjust, exploring whether spouse gender moderated their associations. Findings indicated that the association of (1) spouses' perceptions of their own mental functioning with spouses' and service members' adjustment and (2) spouses' mental readiness for deployment with service members' adjustment both differed by spouse gender, with associations attenuated for male spouses and their service member partners. Other factors associated with family adjustment included the spouse's satisfaction with communication, the extent to which the service member shared deployment experiences, the extent to which the spouse was bothered by deployment experiences, the spouse's participation in postdeployment transition programs, the spouse's informal support during deployment, and length of deployment. Results indicated shared and gender-specific risk and protective factors associated with spouse and service member adjustment, demonstrating the importance of tailored military family support programs addressing the needs of different populations of military spouses.

Development and Validation of the Veteran Military Occupational and Environmental Exposure Assessment Tool

INTRODUCTION

Military exposures may present a cumulative load and increased individual susceptibility to negative health outcomes. Currently, there are no comprehensive and validated environmental exposure assessment tools covering the full spectrum of occupational and environmental exposures for Veterans. The Veterans Affairs (VA) War Related Illness and Injury Study Center in Washington, DC, developed the Veteran Military Occupational and Environmental Exposure Assessment Tool (VMOAT) to establish a structured, comprehensive self-report tool that captures military and non-military occupational and environmental exposures. The VMOAT is clinically insightful, modular, and flexible for adding novel exposures, meeting the needs of modern evolving threats and exposures in both clinical and research settings. This manuscript reviews the ongoing development and validation plans for the VMOAT.

MATERIALS AND METHODS

The VMOAT is a self-reported structured questionnaire, and VMOAT 1.0 was developed to cover an individual's 3 life phases (pre, during, post-military service); 5 exposure domains (chemical, physical, biological, injuries including ergonomic, and psychological stress exposures, plus military preventive health measures); and 64 specific exposures nested within exposure categories. VMOAT 1.0 addresses exposure dose (frequency, duration, proximity, route), and can be administered online via VA approved Qualtrics survey software. VMOAT 1.0 to 2.0 updates began in December 2022 with changes focused on readability, streamlining the exposure history, refining the exposure metrics, and improving the skip logic embedded within the survey design.

RESULTS

The initial VMOAT 1.0 development included face and construct validation with expert internal and external academic and military collaborators, undergoing an iterative 5-cycle review as well as sample testing among a small group of Veterans. The VMOAT 1.0 was used in Institutional Review Board (IRB)-approved longitudinal study, which has been examined preliminarily to compare the VMOAT 1.0 with other exposure assessments and to compare responses of Explosive Ordnance Disposal Veterans, a high occupational exposure cohort, to non-Explosive Ordnance Disposal Veterans. Ongoing VMOAT 2.0 updates will include integration of experiences from piloting the VMOAT 1.0 as well as additional face and content validation and survey cognitive testing with Veterans. VMOAT 2.0 data will improve the development of exposure-informed models using composite survey data to create scored- and scale-based exposure metrics for specific exposures and exposure domains. These data will highlight the effectiveness of the VMOAT as a structured comprehensive occupational and environmental exposure assessment instrument.

CONCLUSIONS

VMOAT development supports the 2022 Promise to Address Comprehensive Toxics Act and fits into the existing VA exposure assessment approach as a standardized, comprehensive self-reported exposure assessment tool. It can be utilized as a stand-alone instrument or supplemented by clinician interviews in research or specialty evaluation programs. The collected VMOAT self-report information on military occupational and environmental exposures will allow direct evaluation with objective measures of exposure and health outcomes. These data outcomes have a high potential to guide the DoD and VA environmental exposure risk mitigation and risk communication efforts.

Sexual Assault Research in the Military: Is Oversampling Necessary for Representativeness?

INTRODUCTION

Sexual assault in the U.S. Military is a serious concern. Recruiting representative samples of service members to participate in sexual assault research is essential for understanding the scope of the problem and generating data that can inform prevention and intervention efforts. Accordingly, the current study aims to examine response and completion rates of an anonymous survey of sexual assault and alcohol use among active duty sailors aged 18 to 24 with the overarching goal of achieving a representative sample and informing future recruitment efforts.

MATERIALS AND METHODS

This study was approved by the Institutional Review Board at the Naval Health Research Center. The study involved an anonymous survey of sexual assault and alcohol use among 612 active duty sailors aged 18 to 24. Since 79.6% of Navy service members are men and 20.4% are women, women were oversampled to achieve sufficient representation. Survey invitations were emailed to 12,031 active duty sailors: 64.3% (n = 7,738) men and 35.7% (n = 4,293) women.

RESULTS

Response rates were disproportionate, with 3.0% (n = 234) of male and 8.8% (n = 377) of female sailors responding to the study invitation. Survey completion rates, however, were similar between male and female sailors (81.2% and 80.1% for male and female personnel, respectively).

CONCLUSION

Results demonstrated that female sailors were significantly more likely than male sailors to participate in a study of sexual assault and alcohol use. However, once enrolled in the study, male and female sailors completed the 234-item questionnaire at a similar rate. Study findings highlight the challenges of engaging male service members in sexual assault-related research. Despite the disproportionately high representation of men in the military, sexual assault researchers may need to sample according to the overall distribution of gender in the military or perhaps even oversample men to achieve a representative sample.

Risk of Traumatic Brain Injury in Deployment and Nondeployment Settings Among Members of the Millennium Cohort Study

OBJECTIVE

To describe and quantify the prevalence and risk of deployment and nondeployment service-related traumatic brain injury (TBI) among participants of the Millennium Cohort Study.

SETTING

Survey data.

PARTICIPANTS

28 759 Millennium Cohort Study participants who were active duty, Reserves, or National Guard at the time of the survey.

DESIGN

Cross-sectional secondary data analysis.

MAIN MEASURES

Estimates of prevalence and rates of TBI were calculated. Multivariable Poisson regression estimated rate ratios of TBI overall and stratified by deployment and nondeployment settings.

RESULTS

The rate of TBI over the 362 535 person-years (PY) was 2.95 p/100 PY. the nondeployment rate was 2.15 p/100 PY, with a significantly higher rate (11.38 p/100 PY) in deployment settings. Bullets/blasts were the most common TBI mechanisms in deployed settings, while sports/physical training and military training were common in nondeployed settings.

CONCLUSIONS

The risk of TBI as well as its mechanism varies by deployment and nondeployment, suggesting that targeted prevention strategies are needed to reduce the risk for TBI among military personnel based on their deployment status.

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.

Long-term consequences of mothers' and fathers' wartime deployments: Protocol for a two-wave panel study

Multiple adjustment difficulties have been associated with children's exposure to recent parental wartime military deployments, but long-term consequences have not yet been systematically studied. This investigation will assess direct and indirect relationships between exposures to parental deployments early in life and later youth adjustment. Parents' psychological health and family processes will be examined as mediators, and parents' and children's vulnerability and support will be examined as moderators. Archival data will be combined with new data gathered from two children and up to two parents in families where children will be aged 11 to 16 at the first data collection and will have experienced at least one parental deployment, for at least one child prior to age 6. Data are being gathered via telephone interviews and web-based surveys conducted twice one year apart. Outcomes are indicators of children's social-emotional development, behavior, and academic performance. Notable features of this study include oversampling of female service members, inclusion of siblings, and inclusion of families of both veterans and currently serving members. This study has potentially important implications for schools, community organizations and health care providers serving current and future cohorts of military and veteran families.

Three-Item Dimensions of Anger Reactions Scale

Importance

Problematic anger is prevalent and associated with adjustment difficulties in military populations. To facilitate measurement of problematic anger, a very brief valid measure is needed.

Objective

To reduce the Dimensions of Anger Reactions 5-item (DAR-5) scale to a very brief measure.

Design, Setting, and Participants

This cross-sectional study used survey data collected between 2014 and 2016 in the Australian Transition and Well-Being Research Programme and US Millennium Cohort Study. Participants were service members who were actively serving or had transitioned out of the military (separated). Statistical analyses were performed from September 2021 to June 2023.

Main Outcomes and Measures

The DAR-5 was reduced to the 3 experiential items: frequency, intensity, and duration (the DAR-3). Psychometrics for the DAR-3 and DAR-5 were compared in terms of standardized Cronbach α, positive screening result, mean, and SD. Analyses were stratified by Australian and US military service status cohorts (active duty and separated).

Results

A total of 71 010 participants were included from Australia and the US. Of 10 900 Australian participants (8145 active duty participants [74.7%]; 2755 separated participants [25.3%]), 5893 (55.2%) were aged 40 years or older and 8774 (80.5%) were male; of 60 110 US participants (24 706 active duty participants [41.1%]; 35 404 separated participants [58.9%]), 28 804 (47.9%) were aged 30 to 39 years and 43 475 (72.3%) were male. The DAR-3 demonstrated good internal consistency in the active duty (Australia: mean [SD] score, 4.97 [2.5]; α = 0.90; US: mean [SD] score, 5.04 [2.6]; α = 0.87) and separated (Australia: mean [SD] score, 6.53 [3.4]; α = 0.92; US: mean [SD] score, 6.05 [3.2]; α = 0.91) samples. The cutoff score of 8 or greater on the DAR-3 had optimal sensitivity and specificity across all samples. DAR-3 and DAR-5 were associated with posttraumatic stress disorder (PTSD), depression, aggression, and relationship conflict. While the scales did not significantly differ in their associations with PTSD, depression, and relationship conflict, the magnitude of association for aggression was significantly lower in US samples using the DAR-3 (eg, US active duty sample: DAR-5 OR, 9.96; 95% CI, 9.01-11.00; DAR-3 OR, 8.36; 95% CI, 7.58-9.22).

Conclusions and Relevance

In this cross-sectional study of a very brief measure of anger, each item contributed to the overall strength of the measure without losing psychometric strength compared with the DAR-5. The consistency of these findings across military and veteran samples in Australian and US populations demonstrated the psychometric robustness of the DAR-3.

Racial, Ethnic, and Sex Disparities in Mental Health Among US Service Members and Veterans: Findings From the Millennium Cohort Study

Although disparities in mental health occur within racially, ethnically, and sex-diverse civilian populations, it is unclear whether these disparities persist within US military populations. Using cross-sectional data from the Millennium Cohort Study (2014-2016; n = 103,184; 70.3% male; 75.7% non-Hispanic White), a series of logistic regression analyses were conducted to examine whether racial, ethnic, and/or sex disparities were found in mental health outcomes (posttraumatic stress disorder (PTSD), depression, anxiety, and problematic anger), hierarchically adjusting for sociodemographic, military, health-related, and social support factors. Compared with non-Hispanic White individuals, those who identified as American Indian/Alaska Native, non-Hispanic Black, Hispanic/Latino, or multiracial showed greater risk of PTSD, depression, anxiety, and problematic anger in unadjusted models. Racial and ethnic disparities in mental health were partially explained by health-related and social support factors. Women showed greater risk of depression and anxiety and lower risk of PTSD than men. Evidence of intersectionality emerged for problematic anger among Hispanic/Latino and Asian or Pacific Islander women. Overall, racial, ethnic, and sex disparities in mental health persisted among service members and veterans. Future research and interventions are recommended to reduce these disparities and improve the health and well-being of diverse service members and veterans.

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.

Survey response over 15 years of follow-up in the Millennium Cohort Study

BACKGROUND

Patterns of survey response and the characteristics associated with response over time in longitudinal studies are important to discern for the development of tailored retention efforts aimed at minimizing response bias. The Millennium Cohort Study, the largest and longest running cohort study of military personnel and veterans, is designed to examine the long-term health effects of military service and experiences and thus relies on continued participant survey responses over time. Here, we describe the response rates for follow-up survey data collected over 15 years and identify characteristics associated with follow-up survey response and mode of response (paper vs. web).

METHOD

Patterns of follow-up survey response and response mode (web, paper, none) were examined among eligible participants (n=198,833), who were initially recruited in four panels from 2001 to 2013 in the Millennium Cohort Study, for a follow-up period of 3-15 years (2004-2016). Military and sociodemographic factors (i.e., enrollment panel, sex, birth year, race and ethnicity, educational attainment, marital status, service component, service branch, pay grade, military occupation, length of service, and time deployed), life experiences and health-related factors (i.e., military deployment/combat experience, life stressors, mental health, physical health, and unhealthy behaviors) were used to examine follow-up response and survey mode over time in multivariable generalized estimating equation models.

RESULTS

Overall, an average response rate of 60% was observed across all follow-up waves. Factors associated with follow-up survey response over time included increased educational attainment, married status, female sex, older age, military deployment (regardless of combat experience), and higher number of life stressors, mental health issues, and physical health diagnoses.

CONCLUSION

Despite the challenges associated with collecting multiple waves of follow-up survey data from members of the U.S. military during and after service, the Millennium Cohort Study has maintained a relatively robust response rate over time. The incorporation of tailored messages and outreach to those groups least likely to respond over time may improve retention and thereby increase the representativeness and generalizability of collected survey data.

Occupation and Risk of Traumatic Brain Injury in the Millennium Cohort Study

INTRODUCTION

Traumatic brain injury (TBI) is an occupational health hazard of military service. Few studies have examined differences in military occupational categories (MOC) which take into consideration the physical demands and job requirements across occupational groups.

METHODS

This study was approved by the University of Texas Health Science Center at Houston Institutional Review Board. Data for this cross-sectional study were obtained from the Naval Health Research Center's Millennium Cohort Study, an ongoing DoD study. Univariate analyses were employed to calculate frequencies and proportions for all variables. Bivariate analyses included unadjusted odds ratios (OR) and 95% CI for the association between all variables and TBI. Multivariable logistic regression was used to calculate adjusted ORs and 95% CIs to assess the association between MOC and TBI, adjusted for potential confounders: sex, race/ethnicity, rank, military status, branch of service, before-service TBI, and panel. Logistic regression models estimated odds of TBI for each MOC, and stratified models estimated odds separately for enlisted and officer MOCs.

RESULTS

Approximately 27% of all participants reported experiencing a service-related TBI. All MOCs were statistically significantly associated with increased odds of service-related TBI, with a range of 16 to 45%, except for "Health Care" MOCs (OR: 1.01, 95% CI 0.91-1.13). Service members in "Infantry/Tactical Operations" had the highest odds (OR: 1.45, 95% CI 1.31-1.61) of service-related TBI as compared to "Administration & Executives." Among enlisted service members, approximately 28% reported experiencing a service-related TBI. Among enlisted-specific MOCs, the odds of TBI were elevated for those serving in "Infantry, Gun Crews, Seamanship (OR: 1.79, 95% CI 1.58-2.02)," followed by "Electrical/Mechanical Equipment Repairers (OR: 1.23, 95% CI 1.09-1.38)," "Service & Supply Handlers (OR 1.21, 95% CI 1.08-1.37)," "Other Technical & Allied Specialists (OR 1.21, 95% CI 1.02-1.43)," "Health Care Specialists (OR 1.19, 95% CI 1.04-1.36)," and "Communications & Intelligence (OR: 1.16, 95% CI 1.02-1.31)," compared to "Functional Support & Administration." Among officer service members, approximately 24% reported experiencing a service-related TBI. After adjustment the odds of TBI were found to be significant for those serving as "Health Care Officers" (OR: 0.65, 95% CI: 0.52-0.80) and "Intelligence Officers" (OR: 1.27, 95% CI: 1.01-1.61).

CONCLUSIONS

A strength of this analysis is the breakdown of MOC associations with TBI stratified by enlisted and officer ranks, which has been previously unreported. Given the significantly increased odds of service-related TBI reporting within enlisted ranks, further exploration into the location (deployed versus non-deployed) and mechanism (e.g., blast, training, sports, etc.) for these injuries is needed. Understanding injury patterns within these military occupations is necessary to increase TBI identification, treatment, and foremost, prevention.Results highlight the importance of examining specific occupational categories rather than relying on gross categorizations, which do not account for shared knowledge, skills, and abilities within occupations. The quantification of risk among enlisted MOCs suggests a need for further research into the causes of TBI.

Pre- and Perinatal Risk Factors for Child Maltreatment in Military Families Across the First Two Years of Life

Military families are exposed to a unique constellation of risk factors, which may impact maltreatment outcomes. The present study examined prospective relationships between demographic, health, birth-related, and military-specific risk factors identified prior to a child's birth on their risk for maltreatment in the first two years of life. Data from the Millennium Cohort Study, Department of Defense (DoD) operational records and Family Advocacy Program data on met-criteria maltreatment, and Birth and Infant Health Research program data on suspected maltreatment were linked for 9076 service member parents. Discrete time survival analysis showed that preterm birth increased risk of maltreatment while parents' older age, physical health, and service in the Navy or Air Force decreased risk. Building on DoD's New Parent Support Program, findings suggest the need for universal and targeted prevention efforts, beginning during pregnancy, which limit or eliminate risk factors for maltreatment in military families.

Identifying at-risk marines: A person-centered approach to adverse childhood experiences, mental health, and social support

BACKGROUND

Previous research indicates an association between adverse childhood experiences (ACES) and health outcomes; however, most of these studies rely on variable-centered techniques. This study implemented a person-centered approach to provide a more nuanced understanding of these relations.

METHODS

The sample consisted of 3611 male Marines who completed two surveys, one prior to service and another during or after service. A series of latent class analyses were conducted to identify homogenous subgroups, using ACE categories as indicators. Hierarchical regressions were conducted to examine the relationships between classes, deployment experiences, depression and PTSD, and social support problems.

RESULTS

Five classes were identified: Low Adversity (48.8 %), Low Adversity - Parental Separation (PS; 33.1 %), Elevated Adversity (7.0 %), Moderate Adversity - Violence/Safety (5.7 %), and Moderate Adversity - Parental Loss (PL; 5.4 %). Several classes were associated with outcomes; in reference to Low Adversity, Moderate Adversity - PL was associated with depression and PTSD, Elevated Adversity was associated with PTSD and social support problems, and Low Adversity - PS was associated with social support problems. Experiencing moderate to high combat appeared to modify the associations between Moderate Adversity - PL and depression and PTSD.

LIMITATIONS

Study sample was limited to U.S. Marines; ACEs indicators were limited to specific categories, not allowing for a full range of potential childhood traumatic experiences.

CONCLUSIONS

Findings suggest a nuanced connection between ACEs and mental health; using specific patterns of ACEs, particularly multifaceted indicators of adversity that are inclusive of parental absence may have more utility than the sheer number of ACEs as an indicator for those who may at a heightened risk for mental health concerns.

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.

Single and repeated high-level blast, low-level blast, and new-onset self-reported health conditions in the U.S. Millennium Cohort Study: An exploratory investigation

Introduction

Although previous research suggests that overpressure exposure from either high-level blast (HLB) or low-level blast (LLB) are harmful to health, to date no large-scale studies with representative samples of military personnel have utilized prospective designs and self-reported measures to examine the relationships between blast exposure and health conditions. To address these limitations, this analysis of data from the Millennium Cohort Study (MCS), the largest and longest running study of U.S. service members and veterans, examined (1) whether single or repeated HLB exposure is associated with self-reported diagnoses of illness and injury, (2) whether repeated HLB is associated with greater risk than single HLB, (3) potential adverse consequences of LLB exposure using military occupation as a proxy, and (4) the combined effects of single or repeated HLB and LLB exposure.

Method

MCS participants who completed the 2011-2013 survey (N = 138,949) were classified as having been exposed to "no," "single," or "repeated" HLB exposure, and into low or high risk of exposure to LLB based on occupation. Participants self-reported diagnosis of 45 medical conditions; newly reported diagnoses were regressed on single and repeated (vs. no) HLB, occupational risk of LLB, and relevant interactions using logistic regression.

Results

Single and repeated HLB were associated with new onset of 25 and 29 diagnoses, respectively; repeated HLB exposure was associated with greater risk than single HLB exposure for five diagnoses (e.g., PTSD, depression). Occupational risk of LLB was associated with 11 diagnoses (e.g., PTSD, significant hearing loss). Additionally, 14 significant interactions were detected across 11 diagnoses.

Discussion

Findings suggest that overpressure exposure (including single HLB, repeated HLB, and occupational risk of LLB) may increase the risks of self-reporting clinical diagnoses of PTSD, hearing loss, chronic fatigue syndrome, neuropathy-caused reduced sensation in the hands and feet, depression, vision loss, sinusitis, reflux, and anemia. Furthermore, the combination of HLB and LLB exposure may be associated with greater risk of migraines, PTSD, and impaired fecundity. These findings provide further evidence of the potential adverse consequences associated with overpressure exposure and underscore the necessity of public health surveillance initiatives for blast exposure and/or safety recommendations for training and operational environments.

The bi-directional relationship between post-traumatic stress disorder and obstructive sleep apnea and/or insomnia in a large U.S. military cohort

OBJECTIVES

Determine if a bi-directional relationship exists between the development of sleep disorders (obstructive sleep apnea [OSA] and/or insomnia) and existing post-traumatic stress disorder (PTSD), and vice versa; and examine military-related factors associated with these potential relationships.

DESIGN

Longitudinal analyses of a prospective representative U.S. military cohort.

PARTICIPANTS

Millennium Cohort Study responders in 2011-2013 (Time 1 [T1]) and 2014-2016 (Time 2 [T2]) without insomnia or OSA at T1 (N = 65,915) or without PTSD at T1 (N = 71,256).

MEASUREMENTS

Provider-diagnosed OSA, self-reported items for insomnia, provider-diagnosed PTSD, and current PTSD symptoms were assessed at T1 and T2. Adjusted multivariable models identified military-related factors associated with new-onset PTSD in those with OSA and/or insomnia, and vice versa.

RESULTS

Self-reported history of provider-diagnosed PTSD without current symptoms at T1 was associated with new-onset OSA only and comorbid OSA/insomnia at T2, while current PTSD symptoms and/or diagnosis was associated with new-onset insomnia only. OSA/insomnia at T1 was consistently associated with newly reported PTSD symptoms or diagnosis except that insomnia only was not associated with newly reported provider-diagnosed PTSD. Military-related risk factors significantly associated with the bi-directional relationship for new-onset PTSD or OSA/insomnia included prior deployment with higher combat exposure and recent separation from the military; being an officer was protective for both outcomes.

CONCLUSIONS

In this large military cohort, findings suggest that PTSD and OSA and/or insomnia are bi-directionally predictive for their development, which was sometimes revealed by health care utilization. Relevant military-related risk factors should be considered in efforts to prevent or treat PTSD and/or sleep disorders.

Health Disparities Among Lesbian, Gay, and Bisexual Service Members and Veterans

INTRODUCTION

This study investigated whether health disparities exist among lesbian, gay, and bisexual individuals serving in the U.S. military by examining the associations of sexual orientation with mental, physical, and behavioral health among a population-based sample of service members and veterans.

METHODS

Sexual orientation and health outcomes were self-reported on the 2016 Millennium Cohort Study follow-up questionnaire (N=96,930). Health outcomes were assessed across 3 domains: mental health (post-traumatic stress disorder, depression, anxiety, binge eating, problematic anger), physical health (multiple somatic symptoms, physical functioning, BMI), and behavioral health (smoking, problem and risky drinking, insomnia). Adjusted logistic regression models conducted between 2019 and 2022 estimated the associations between sexual orientation and each health outcome.

RESULTS

Lesbian, gay, and bisexual individuals (3.6% of the sample) were more likely to screen positive for post-traumatic stress disorder, depression, anxiety, binge eating, problematic anger, multiple somatic symptoms, and insomnia than heterosexual individuals. Gay/lesbian and bisexual women reported more adverse health outcomes (overweight and obesity, smoking, problem/risky drinking) than heterosexual women. Gay and bisexual men reported some adverse health outcomes (e.g., smoking and problem drinking) but better physical health (e.g., less overweight/obesity) than heterosexual men.

CONCLUSIONS

Lesbian, gay, and bisexual service members reported poorer mental, physical, and behavioral health than heterosexual peers, most notably among gay/lesbian women and bisexual individuals. Findings suggest that lesbian, gay, and bisexual service members experience health disparities, despite many having equal eligibility for health care, highlighting the need for improved equity initiatives that promote cultural responsiveness, acceptance, and approaches to support the healthcare needs of lesbian, gay, and bisexual military members.

The relative impact of injury and deployment on mental and physical quality of life among military service members

US service members injured in the recent conflicts in Iraq and Afghanistan were more likely to survive than those in previous conflicts because of advances in medicine and protective gear. However, there is limited research examining the long-term impact of injuries while deployed on physical and mental quality of life (QOL) among service members. We used data from two time-points with an average follow-up period of 4.27 years (SD = 2.13; n = 118,054) to prospectively examine the association between deployment and injury status with QOL. Data were derived from the Millennium Cohort Study surveys (2001 to 2016) and linked with the Department of Defense Trauma Registry (DoD-TR) among a cohort of US service members from all branches and components. The primary predictor (a combination of deployment and injury status) was comprised of the following four categories: 1) not deployed, 2) deployed and not injured, 3) deployed and non-battle injured, and 4) deployed and battle injured. Demographic, military, psychological and behavioral health, and life stress factors were adjusted for in multivariable models. Outcomes of interest were physical and mental QOL from the Short-Form Health Survey for Veterans (VR-36) measured at ~4 year follow-up. Between group comparisons indicated that those deployed and battle-injured had the greatest decline in both mental (-3.82) and physical (-10.13) QOL scores over time (p < .05). While deployment and injury status were associated with poorer mental and physical QOL in adjusted models; only the association between deployment and injury status with physical QOL was clinically meaningful (more than 2.5). In adjusted models, Time 1 mental and physical QOL explained most of the variance (23–25%) in Time 2 mental and physical health QOL as compared to other covariates (e.g., injury and deployment, and other sociodemographic factors increased variance by ~5%). Time 1 QOL was the most significant predictor of later QOL, but those injured while deployed experienced significant and meaningful decrements to long-term physical QOL. This suggests that prevention and rehabilitation interventions should focus on improving physical health among injured service members to avoid long-term adverse effects.

Association of Problematic Anger With Long-term Adjustment Following the Military-to-Civilian Transition

Importance

Few studies have examined the role of problematic anger in long-term adjustment of service members transitioning out of the military.

Objective

To determine the prevalence of problematic anger during the military-to-civilian transition period and the association of problematic anger with adjustment to civilian life.

Design, Setting, and Participants

This cohort study used 2 waves of survey data administered approximately 5 years apart (time 1 [T1; September 26, 2014, to August 25, 2016] and time 2 [T2; October 23, 2019, to August 31, 2021]) from the Millennium Cohort Study, a population-based military study. Participants were US active-duty service members within 24 months of separating from military service at T1. Statistical analysis was performed from September 2021 to May 2022.

Exposures

Problematic anger was operationalized as scoring at least 12 points on the 5-item Dimensions of Anger Reactions scale at T1.

Main Outcomes and Measures

Behavioral and functional health (depression, posttraumatic stress disorder, problem drinking, functional limitations), relationship health (relationship quality, coping with parental demands, social support), and economic health (major financial problems, financial insecurity, homelessness, employment status) were assessed at T2. Covariates, assessed at T1, included demographics, military characteristics, mental health, problem drinking, and physical health.

Results

Of the 3448 participants, 2625 (76.1%) were male, 217 (6.3%) were Hispanic, 293 (8.5%) were non-Hispanic Black, and 2690 (78.0%) were non-Hispanic White; the mean (SD) age was 40.1 (8.5) years; 826 (24.0%) met criteria for problematic anger. Prevalence of problematic anger was 15.9% (95% CI, 12.2%-19.7%) 24 months prior to military separation and 31.2% (95% CI, 26.2%-36.2%) 24 months following separation. After adjusting for covariates, problematic anger was associated with greater likelihood of behavioral and functional health outcomes (eg, posttraumatic stress disorder: adjusted odds ratio, 1.55, 95% CI, 1.23-1.96), relationship health difficulties (eg, low social support: aOR, 1.66; 95% CI, 1.23-2.24), and economic difficulties (eg, substantial financial insecurity: aOR, 1.64; 95% CI, 1.13-2.39) at T2.

Conclusions and Relevance

This cohort study found an association between prevalence of problematic anger during the military-to-civilian transition and problematic anger with subsequent adjustment difficulties among US service members. These findings suggest the need to equip service members proactively with skills to identify and manage anger as a way to support them before and during this period of transition.

Combat exposure and behavioral health in U.S. Army Special Forces

Although combat has been found to be associated with adverse health outcomes, little is known about the impact of specific combat exposures, particularly among specialized personnel. This study examined the association of different types of combat exposures with behavioral health outcomes, and whether these associations differed by Army occupational specialization: General Purpose Forces infantrymen (n = 5,361), Ranger Qualified infantrymen (n = 308), and Special Forces personnel (n = 593). Multivariable regression models estimated the association of combat severity, type of combat event (fighting, killing, threat to oneself, death/injury of others), and type of killing with mental health disorders, trouble sleeping, and problem drinking. Combat severity, each type of combat event, and killing noncombatants were associated with adverse health outcomes after adjusting for covariates and other combat exposures. Except for trouble sleeping, these associations did not differ by occupational specialization, though the prevalence and odds of outcomes were generally lower for Special Forces personnel.

Sexual Health Problems among Service Men: The Influence of Posttraumatic Stress Disorder

Military operational stressors, such as combat exposure, may increase the risk of sexual health problems. This study examined factors associated with sexual health problems, and tested the mediating effect of probable posttraumatic stress disorder (PTSD) on the association between stressors (i.e., combat deployment and sexual assault) and sexual health problems among U.S. service men. Using multivariable logistic regression (n = 16,603) and Cox proportional hazards models (n = 15,330), we estimated the risk of self-reported sexual health difficulties and sexual dysfunction medical encounters, respectively. Mediation analyses examined the effect of probable PTSD as an intermediate factor between high combat deployment and sexual assault on sexual health problems. Approximately 9% endorsed sexual health difficulties and 8% had a sexual dysfunction. Risk factors for these sexual health problems included older age, lower education level, enlisted rank, disabling injury, certain medical conditions, and higher body mass index. Probable PTSD significantly mediated the associations between high combat with sexual health problems and sexual assault with sexual dysfunction. Additionally, high combat was directly associated with sexual health difficulties. These findings indicate a relationship between these stressors and sexual health problems which suggests that treatment options should be expanded, especially to include psychogenic sexual dysfunctions.

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.

A temporal analysis of mental health symptoms relative to separation from the military

BACKGROUND

The transition from military to civilian life is a dramatic change that is often stressful for veterans. However, little is known regarding how mental health symptoms fluctuate in the period leading up to and following separation from the military.

METHODS

The current study examined posttraumatic stress disorder and depression symptoms reported on surveys completed within 1 year of military separation from 23,887 active duty Millennium Cohort Study participants. A series of general linear models and graphs stratified by demographic and military characteristics examined the association between time until/since separation and mental health symptoms.

RESULTS

Character of discharge had the most striking relationship between time until/since separation and mental health. Personnel with Honorable discharges did not differ in their level of mental health symptoms across the study period. In contrast, personnel with Other than Honorable/General discharges reported normal levels of mental health symptoms 1 year-prior to separation but reported progressively greater symptoms leading to separation which persisted through the remainder of study period.

CONCLUSIONS

This study suggests that additional outreach is needed for personnel with Other than Honorable/General discharges. However, for most other personnel, increased mental health symptomatology around military separation is not a normative phenomenon and any instance should be treated promptly.

Factors Associated with Human Papillomavirus Vaccine Initiation and Compliance Among U.S. Military Service Members

INTRODUCTION

The primary objective of the current study was to assess factors associated with Human Papillomavirus (HPV) vaccine initiation and compliance in a cohort of active duty US military service members (SM).

MATERIALS AND METHODS

We included active-duty participants aged 18-26 years from the Millennium Cohort Study, a longitudinal cohort study of over 200,000 military SMs. The eligible study population included 22,387 female SMs and 31,705 male SMs. Vaccination was assessed over the period 2006-2017. Logistic regression was used to estimate the odds of vaccine initiation and compliance (3 doses within a 1-year period) in relation to demographic, military, health, and behavioral characteristics.

RESULTS

Among female SMs, 37.8% initiated the vaccine and 40.2% of initiators completed the series within a year. Among male SMs, 3.9% initiated the vaccine and 22.1% of initiators completed the series within a year. Differences by sociodemographic factors, deployment status, branch of service, occupation, and smoking status-but not by selected mental health conditions-were observed.

CONCLUSION

HPV vaccination uptake is subpar across all military service branches. Certain subgroups of SMs could be targeted to increase overall HPV vaccine coverage in the US military population.

Problematic anger and economic difficulties: Findings from the Millennium Cohort Study

BACKGROUND

The role of problematic anger in relation to economic difficulties is not well understood. This study examined the association of problematic anger with 4 elements of economic difficulties among service members and veterans.

METHODS

Study participants (n = 95,895) were from the Millennium Cohort Study, and included U.S. service members and veterans; analyses were restricted to a Reserve/National Guard and/or veteran sample as appropriate. Key measures included the Dimensions of Anger Reactions scale and self-reported economic variables (involuntary job loss, financial problems, unemployment and homelessness). Covariates included demographics, military characteristics, disabling injury or illness, problem drinking, posttraumatic stress disorder, and major depressive disorder. The study design was cross-sectional.

RESULTS

Among all participants, 17.4% screened positive for problematic anger, 29.7% reported involuntary job loss, and 6.4% reported financial problems. After adjustment for covariates, problematic anger was associated with involuntary job loss (AOR=1.28; 95% CI: 1.22, 1.33) and financial problems (AOR=1.46; 95% CI: 1.36, 1.57). Among veterans, 12.1% reported being unemployed; among Reserve/National Guard and veterans, 2.3% reported homelessness. Problematic anger was associated with unemployment (AOR=1.28, 95% CI: 1.18, 1.37) and homelessness (AOR=1.33; 95% CI: 1.16, 1.52) after adjusting for covariates.

LIMITATIONS

The study relied on self-report data and directionality could not be established.

CONCLUSIONS

Problematic anger was significantly associated with involuntary job loss, financial problems, unemployment and homelessness, even after adjusting for relevant covariates. These findings have clinical relevance in demonstrating the potential for targeting problematic anger in service members and veterans.

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.

The Millennium Cohort Study: The First 20 Years of Research Dedicated to Understanding the Long-Term Health of US Service Members and Veterans

The Millennium Cohort Study, the US Department of Defense's largest and longest running study, was conceived in 1999 to investigate the effects of military service on service member health and well-being by prospectively following active duty, Reserve, and National Guard personnel from all branches during and following military service. In commemoration of the Study's 20th anniversary, this paper provides a summary of its methods, key findings, and future directions. Recruitment and enrollment of the first 5 panels occurred between 2001 and 2021. After completing a baseline survey, participants are requested to complete follow-up surveys every 3 to 5 years. Study research projects are categorized into 3 core portfolio areas (psychological health, physical health, and health-related behaviors) and several cross-cutting areas and have culminated in more than 120 publications to date. For example, some key Study findings include that specific military service-related factors (e.g., experiencing combat, serving in certain occupational subgroups) were associated with adverse health-related outcomes and that unhealthy behaviors and mental health issues may increase following the transition from military service to veteran status. The Study will continue to foster stakeholder relationships such that research findings inform and guide policy initiatives and health promotion efforts.

Prevalence and predictors of insomnia and sleep medication use in a large tri-service US military sample

OBJECTIVE

The presence of insomnia in the general military population is not well known. This study aimed to determine the prevalence of probable clinical insomnia and identify factors leading to new-onset insomnia and/or sleep medication use in a large military population.

DESIGN

Cross-sectional and longitudinal analyses of a prospective cohort study.

PARTICIPANTS

A tri-service US military and veteran cohort (sample range 99,383-137,114).

MEASUREMENTS

Participants were surveyed in 2013 (Time 1 [T1]) and 2016 (Time 2 [T2]) using the clinically validated Insomnia Severity Index. The prevalence of insomnia and sleep medication use was quantified at both times. Multivariable models identified military factors associated with new-onset insomnia and/or sleep medication use while adjusting for covariates.

RESULTS

The prevalence of insomnia at T1 and T2 was 16.3% and 11.2%, respectively. New-onset insomnia at T2 was reported by 6.0% of participants screening negative at T1; risk factors included Army service, combat deployment experience, and separation from military service. The prevalence of sleep medication use at T1 and T2 was 23.1% and 25.1%, respectively. Sleep medication use at T2 was newly-reported by 17.1% of participants not reporting sleep medication use at T1; risk factors included number of deployments and having a healthcare occupation.

CONCLUSIONS

The prevalence of probable clinical insomnia in this large general military population is within the range of previous reports in military and civilian populations. Certain military factors that predict new-onset insomnia and/or sleep medication use should be considered when designing and implementing sleep interventions in military populations.

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 health difficulties among service women: the influence of posttraumatic stress disorder

Background Sexual health among service women remains understudied, yet is related to health and quality of life. This study examined if the associations between recent combat and sexual assault with sexual health difficulties were mediated by mental disorders and identified factors associated with sexual health difficulties among service women. Methods Data from two time points (2013 and 2016) of the Millennium Cohort Study, a large military cohort, were used. The outcome was self-reported sexual health difficulties. Mediation analyses examined probable posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) as intermediate variables between recent combat and sexual assault with the sexual health difficulties. Multivariable logistic regression modeling was used to examine the association of demographic, military, historical mental health, life stressors, and physical health factors with sexual health difficulties. Results Of the 6,524 service women, 13.5% endorsed experiencing sexual health difficulties. Recent combat and sexual assault were significantly associated with sexual health difficulties. Probable PTSD mediated the associations of recent combat and sexual assault with sexual health difficulties; probable MDD did not mediate these relationships. Other significant factors associated with sexual health difficulties included enlisted rank, historical mental disorders, childhood trauma, and disabling injury. Limitations Use of self-reported data, outcome not assessed using a standardized measure and future studies may benefit from examining other mediators. Conclusion Our findings that combat and sexual assault may have negative effects on service women's sexual health suggest that treatment options and insurance coverage for sexual health problems should be expanded.

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.

Longitudinal associations of military-related factors on self-reported sleep among U.S. service members

STUDY OBJECTIVES

Sleep loss is common in the military, which can negatively affect health and readiness; however, it is largely unknown how sleep varies over a military career. This study sought to examine the relationships between military-related factors and the new onset and reoccurrence of short sleep duration and insomnia symptoms.

METHODS

Millennium Cohort Study data were used to track U.S. military service members over time to examine longitudinal changes in sleep. Outcomes were self-reported average sleep duration (categorized as ≤5 hours, 6 hours, or 7-9 hours [recommended]) and/or insomnia symptoms (having trouble falling or staying asleep). Associations between military-related factors and the new onset and reoccurrence of these sleep characteristics were determined, after controlling for multiple health and behavioral factors.

RESULTS

Military-related factors consistently associated with an increased risk for new onset and/or reoccurrence of short sleep duration and insomnia symptoms included active duty component, Army or Marine Corps service, combat deployment, and longer than average deployment lengths. Military officers and noncombat deployers had decreased risk for either sleep characteristic. Time-in-service and separation from the military were complex factors; they lowered risk for ≤5 hours sleep but increased risk for insomnia symptoms.

CONCLUSIONS

Various military-related factors contribute to risk of short sleep duration and/or insomnia symptoms over time, although some factors affect these sleep characteristics differently. Also, even when these sleep characteristics remit, some military personnel have an increased risk of reoccurrence. Efforts to improve sleep prioritization and implement interventions targeting at-risk military populations, behaviors, and other significant factors are warranted.

Longitudinal Investigation of Military-specific Factors Associated With Continued Unhealthy Alcohol Use Among a Large US Military Cohort

To examine whether military separation (Veteran), service component (active duty, Reserve/National Guard), and combat deployment are prospectively associated with continuing unhealthy alcohol use among US military service members.

Hyperarousal symptoms and decreased right hemispheric frontolimbic white matter integrity predict poorer sleep quality in combat-exposed veterans

OBJECTIVE

Disrupted sleep is common following combat deployment. Contributors to risk include posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI); however, the mechanisms linking PTSD, mTBI, and sleep are unclear. Both PTSD and mTBI affect frontolimbic white matter tracts, such as the uncinate fasciculus. The current study examined the relationship between PTSD symptom presentation, lateralized uncinate fasciculus integrity, and sleep quality.

METHOD

Participants include 42 combat veterans with and without PTSD and mTBI. Freesurfer and Tracula were used to establish specific white matter ROI integrity via 3-T MRI. The Pittsburgh Sleep Quality Index and PTSD Checklist were used to assess sleep quality and PTSD symptoms.

RESULTS

Decreased fractional anisotropy in the right uncinate fasciculus (β = -1.11, SE = 0.47, p < .05) and increased hyperarousal symptom severity (β = 3.50, SE = 0.86, p < .001) were associated with poorer sleep quality.

CONCLUSION

Both right uncinate integrity and hyperarousal symptom severity are associated withsleep quality in combat veterans. The right uncinate is a key regulator of limbic behavior and sympathetic nervous system reactivity, a core component of hyperarousal. Damage to this pathway may be one mechanism by which mTBI and/or PTSD could create vulnerability for sleep problems following combat deployment.

Behavioral health and sleep problems among US Army veterinarians and veterinary technicians participating in the Millennium Cohort Study

OBJECTIVE

To determine the prevalences and relative odds of mental health problems, suicidal ideation, psychotropic medication use, problem drinking, trouble sleeping, and lack of social support among veterinarians and veterinary technicians, compared with other medical professionals, in the US Army.

SAMPLE

7,744 US Army personnel (957 officers [101 veterinarians and 856 physicians and dentists] and 6,787 enlisted personnel [334 veterinary technicians and 6,453 medics]) participating in the Millennium Cohort Study.

PROCEDURES

Eligible participants completed ≥ 1 survey while serving as an Army veterinarian, veterinary technician, physician, general dentist, or medic. Analysis methods including multivariable logistic regression adjusted for covariates and stratified by pay grade were used to investigate associations between each health-care occupation and outcomes of interest.

RESULTS

Veterinarians had higher reported prevalences of mental health problems, trouble sleeping, and lack of social support than did nontrauma physicians, trauma physicians, or dentists. On multivariable analysis, veterinarians had higher odds of mental health problems, trouble sleeping, and lack of social support, compared with physicians and dentists combined; odds for these outcomes were also higher for veterinarians, compared with various individual reference groups. Veterinary technicians had lower reported prevalence and lower odds of psychotropic medication use, compared with medics.

CONCLUSIONS AND CLINICAL RELEVANCE

Further examination of Army policies and organizational structures related to veterinarians may be warranted, along with the development of policies and interventions designed to improve mental health, sleep quality, and social support among military veterinarians.

Nightmares and Insomnia in the US National Guard: Mental and Physical Health Correlates

BACKGROUND

Nightmares and insomnia are significant concerns that commonly co-occur with each other and with other health disorders. Limited research has examined the unique and shared aspects of insomnia and nightmares, and little is known about sleep in US National Guard personnel. This study sought to determine the prevalence and psychosocial correlates of nightmares with and without insomnia in US National Guard personnel.

METHOD

National Guard personnel (N = 841) completed an online survey and were classified as having nightmares only, insomnia only, both, or neither, using a minimum nightmare frequency of "less than once a week" and an Insomnia Severity Index cutoff of ≥ 15. Analyses examined differences in demographics, physical health, and psychosocial variables and in the prevalence of nightmares and insomnia in personnel with physical and mental health problems.

RESULTS

In this sample, 32% reported nightmares only, 4% reported insomnia only, and 12% reported both. Those in the youngest age group (18-21) were more likely to have no nightmares or insomnia. Those with both nightmares and insomnia had more deployments. Nightmares and insomnia were associated with poorer physical and mental health and greater prevalence of comorbid physical and mental health conditions. Personnel with both insomnia and nightmares reported the greatest severity of comorbid conditions.

CONCLUSION

US National Guard personnel with nightmares and/or insomnia reported worse mental and physical health impairment than those without these conditions. Personnel may benefit from screening for nightmares and insomnia and referrals for evidence-based treatment.

Comparison of Posttraumatic Stress Disorder Checklist Instruments From Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition vs Fifth Edition in a Large Cohort of US Military Service Members and Veterans

IMPORTANCE

The definition of posttraumatic stress disorder (PTSD) changed markedly between the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) and DSM-5, creating challenges for studies and in medical settings spanning this transition.

OBJECTIVE

To evaluate the ability to compare and assess PTSD, based on DSM-IV and DSM-5 criteria, using PTSD Checklists (PCLs).

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic study was conducted with survey data collected in October 2019, from the Millennium Cohort Study, a population-based US military cohort study. The population for the present study was restricted to a subset of initial web responders of the 2019 survey cycle, randomly assigned to 1 of 4 survey groups.

EXPOSURES

Each group received the DSM-IV and DSM-5 PCL (PCL-Civilian [PCL-C] version and PCL for DSM-5 [PCL-5]). PCL instruments were counterbalanced to control for order effects.

MAIN OUTCOMES AND MEASURES

Survey data were used to assess PTSD (using the PCL-C and PCL-5), major depressive disorder (using the Patient Health Questionnaire), generalized anxiety (using the Generalized Anxiety Disorder scale), and problem drinking (using the Patient Health Questionnaire). Demographic and military characteristics included age, sex, race/ethnicity, marital status, education, service branch, pay grade, enrollment panel, and military service status.

RESULTS

Among the 1921 participants (mean [SD] age, 50.1 [12.5] years), 1358 (70.7%) were men, 1638 (85.3%) were non-Hispanic White individuals, 1440 (75.0%) were married, and 1190 (61.9%) had at least a bachelor's degree; 295 (15.4%) had probable PTSD according to DSM-IV criteria with PCL-C compared with 286 (14.9%) using DSM-5 criteria with PCL-5 (κ = 0.77). There was substantial agreement between PCLs for probable PTSD based on DSM-IV criteria (295 [15.4%] with PCL-C; 316 [16.4%] with PCL-5; κ = 0.80) and DSM-5 criteria (286 [14.9%] with PCL-5; 258 [13.4%] with PCL-C; κ = 0.77). Estimated PTSD sum scores showed excellent agreement with observed scores. Using an established crosswalk, PCL-5 sum scores estimated with the PCL-C were similar to observed PCL-5 scores. Of the 17 corresponding items between the 2 instruments, 16 had substantial agreement. Appending 2 additional PCL-C items to the PCL-5 did not significantly alter estimates. The PCL-C and PCL-5 had nearly identical associations with comorbid conditions.

CONCLUSIONS AND RELEVANCE

The findings of this diagnostic study suggest that PTSD can be successfully assessed and compared over time with either PCL instrument in veteran and military populations.

Association of risk factors with type 2 diabetes: A systematic review

Diabetes is the leading cause of severe health complications and one of the top 10 causes of death worldwide. To date, diabetes has no cure, and therefore, it is necessary to take precautionary measures to avoid its occurrence. The main aim of this systematic review is to identify the majority of the risk factors for the incidence/prevalence of type 2 diabetes mellitus on one hand, and to give a critical analysis of the cohort/cross-sectional studies which examine the impact of the association of risk factors on diabetes. Consequently, we provide insights on risk factors whose interactions are major players in developing diabetes. We conclude with recommendations to allied health professionals, individuals and government institutions to support better diagnosis and prognosis of the disease.

Cause-specific mortality risks among U.S. veterans: 25 years after their service in the 1990-1991 gulf war

PURPOSE

There is concern about adverse health effects related to military service in the 1990-1991 Gulf War. This study assessed cause-specific mortality risks among Veterans who served in the war.

METHODS

The mortality of 621,244 veterans deployed to the Gulf War was compared to that of 745,704 Veterans who served during the war but were not deployed to the Gulf Theater. Cause-specific mortality of both deployed and nondeployed was also compared to that of the US general population.

RESULTS

There was no increased risk of disease-specific mortality among deployed Veterans compared to nondeployed. Deployed Veterans did have an increased risk of motor vehicle deaths compared to nondeployed Veterans, (hazard ratio, 1.12, 95% confidence interval, 1.04-1.21). Cause-specific mortality of both deployed and non-deployed Veterans was less than that of the US population. When stratified by gender, only female Veterans, both deployed and nondeployed, had increased risks of suicide compared to the female US population (standardized mortality ratio, 1.40; 95% confidence interval, 1.13-1.71 and standardized mortality ratio, 1.22; 95% confidence interval, 1.05-1.40, respectively).

CONCLUSION

There was no increased risk of disease mortality among Veterans of the 1990-1991 Gulf War. Both deployed and nondeployed female Veterans had increased risks of suicide compared to US female population.

Association of Combat Experiences With Suicide Attempts Among Active-Duty US Service Members

Importance

There is uncertainty about the role that military deployment experiences play in suicide-related outcomes. Most previous research has defined combat experiences broadly, and a limited number of cross-sectional studies have examined the association between specific combat exposure (eg, killing) and suicide-related outcomes.

Objective

To prospectively examine combat exposures associated with suicide attempts among active-duty US service members while accounting for demographic, military-specific, and mental health factors.

Design, Setting, and Participants

This cohort study analyzed data from the Millennium Cohort Study, an ongoing prospective longitudinal study of US service members from all military branches. Participants were enrolled in 4 phases from July 1, 2001, to April 4, 2013, and completed a self-administered survey at enrollment and every 3 to 5 years thereafter. The population for the present study was restricted to active-duty service members from the first 4 enrollment phases who deployed in support of the wars in Iraq and Afghanistan. Questionnaire data were linked with medical encounter data through September 30, 2015. Data analyses were conducted from January 10, 2017, to December 14, 2020.

Exposures

Combat exposure was examined in 3 ways (any combat experience, overall combat severity, and 13 individual combat experiences) using a 13-item self-reported combat measure.

Main Outcomes and Measures

Suicide attempts were identified from military electronic hospitalization and ambulatory medical encounter data using the International Classification of Diseases, Ninth Revision codes.

Results

Among 57 841 participants, 44 062 were men (76.2%) and 42 095 were non-Hispanic White individuals (72.8%), and the mean (SD) age was 26.9 (5.3) years. During a mean (SD) follow-up period of 5.6 (4.0) years, 235 participants had a suicide attempt (0.4%). Combat exposure, defined broadly, was not associated with suicide attempts in Cox proportional hazards time-to-event regression models after adjustments for demographic and military-specific factors; high combat severity and certain individual combat experiences were associated with an increased risk for suicide attempts. However, these associations were mostly accounted for by mental disorders, especially posttraumatic stress disorder. After adjustment for mental disorders, combat experiences with significant association with suicide attempts included being attacked or ambushed (hazard ratio [HR], 1.55; 95% CI, 1.16-2.06), seeing dead bodies or human remains (HR, 1.34; 95% CI, 1.01-1.78), and being directly responsible for the death of a noncombatant (HR, 1.81; 95% CI, 1.04-3.16).

Conclusions and Relevance

This study suggests that deployed service members who experience high levels of combat or are exposed to certain types of combat experiences (involving unexpected events or those that challenge moral or ethical norms) may be at an increased risk of a suicide attempt, either directly or mediated through a mental disorder.

Posttraumatic Stress Disorder Symptom Clusters in Service Members Predict New-Onset Depression Among Military Spouses

Military operations in Iraq and Afghanistan have brought increased attention to posttraumatic stress disorder (PTSD) among service members and, more recently, its impact on spouses. Existing research has demonstrated that PTSD among service members is associated with depression among military spouses. In the current study, we extended these findings by using data from service member-spouse dyads enrolled in the Millennium Cohort Family Study for which the service member had evidence of PTSD (n = 563). Prospective analyses identified the association between PTSD symptom clusters reported by the service member and new-onset depression among military spouses. Over the 3-year study period, 14.4% of these military spouses met the criteria for new-onset depression. In adjusted models, service member ratings of symptoms in the effortful avoidance cluster, odds ratio (OR) = 1.61, 95% CI [1.03, 2.50], predicted an increased risk of new-onset depression among military spouses, whereas reexperiencing symptoms, adjusted OR = 0.57; 95% CI [0.32, 1.01], were marginally protective. These findings suggest that PTSD symptom clusters in service members differentially predict new-onset depression in military spouses, which has implications for treatment provision.

Multiple imputation validation study: addressing unmeasured survey data in a longitudinal design

Background

Questionnaires used in longitudinal studies may have questions added or removed over time for numerous reasons. Data missing completely at a follow-up survey is a unique issue for longitudinal studies. While such excluded questions lack information at one follow-up survey, they are collected at other follow-up surveys, and covariances observed at other follow-up surveys may allow for the recovery of the missing data. This study utilized data from a large longitudinal cohort study to assess the efficiency and feasibility of using multiple imputation (MI) to recover this type of information.

Methods

Millennium Cohort Study participants completed the 9-item Patient Health Questionnaire (PHQ) depression module at 2 time points (2004, 2007). The suicidal ideation item in the module was set to missing for the 2007 assessment. Several single-level MI models using different sets of predictors and forms of suicidal ideation were used to compare self-reported values and imputed values for this item in 2007. Additionally, associations with sleep duration and smoking status, which are related constructs, were compared between self-reported and imputed values of suicidal ideation.

Results

Among 63,028 participants eligible for imputation analysis, 4.05% reported suicidal ideation on the 2007 survey. The imputation models successfully identified suicidal ideation, with a sensitivity ranging between 34 and 66% and a positive predictive value between 36 and 42%. Specificity remained above 96% and negative predictive value above 97% for all imputed models. Similar associations were found for all imputation models on related constructs, though the dichotomous suicidal ideation imputed from the model using only PHQ depression items yielded estimates that were closest with the self-reported associations for all adjusted analyses.

Conclusions

Although sensitivity and positive predictive value were relatively low, applying MI techniques allowed for inclusion of an otherwise missing variable. Additionally, correlations with related constructs were estimated near self-reported values. Therefore, the other 8 depression items can be used to estimate suicidal ideation that was completely missing from a survey using MI. However, these imputed values should not be used to estimate population prevalence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-020-01158-w.

Combat Experience, New-Onset Mental Health Conditions, and Posttraumatic Growth in U.S. Service Members

Objective: Studies examining posttraumatic growth (PTG) rely on surveys evaluating PTG in relation to prior traumatic experiences, resulting in psychometric problems due to the linkage of the dependent and independent variables. Few studies have assessed PTG following combat deployment while also controlling for mental health problems.Method: Longitudinal data on PTG, combat experience, and mental health were examined among U.S. Millennium Cohort Study deployers (n = 8732). Scores from a short-form (SF) version of the PTG inventory assessing current-state beliefs (C-PTGI-SF) independent of any predictor variables were assessed at time 1 (T1), before deployment, and change in scores were assessed approximately 3 years later after deployment at time 2 (T2). All participants screened negative for posttraumatic stress disorder (PTSD) and depression at T1.Results: Combat deployment severity was associated with a worsening of C-PTGI-SF scores at T2 among participants with moderate C-PTGI-SF scores at T1. A positive screen for comorbid PTSD/depression was associated with a worsening of C-PTGI-SF scores at T2 among participants with moderate or high C-PTGI-SF scores at T1. At T2, a strong inverse correlation was found between C-PTGI-SF scores and PTSD (r = -0.38) and depression (-0.41). Only 5% of participants who screened positive for a mental health problem at T2 (23/517) also experienced positive growth.Conclusions: These results challenge the clinical utility of the PTG construct. While PTG may be a useful framework for supporting trauma recovery on an individual basis, PTG does not appear to be distinct and independent from the negative psychological impact of traumatic experiences.

Alcohol misuse and separation from military service: A dyadic perspective

OBJECTIVE

Alcohol misuse is a prevalent problem among military service members and their spouses. Service member alcohol misuse may contribute to poor job performance, legal infractions, and failure to meet physical standards. Spousal alcohol misuse may indicate problems with military life. However, limited information is available about how alcohol misuse in military families affects occupational outcomes, specifically military attrition.

METHOD

The current study examined 7,965 opposite sex married couples from the Millennium Cohort Family Study with one military and one civilian/veteran partner. Both partners reported on three measures of alcohol misuse (binge drinking, alcohol problems, and heavy weekly drinking). The associations between each partner's measures of alcohol misuse and subsequent military separation were evaluated using logistic regression. Sex, concordance of alcohol misuse, mental health, and service branch were explored as moderators.

RESULTS

In fully adjusted models, service member alcohol problems were directly related to military separation. Additionally, service member heavy weekly drinking was strongly associated with military separation among female service members but not male service members. Service member and spouse binge drinking interacted such that when only one partner reported binge drinking military separation was less likely, but both partners' binge drinking conveyed a marginally increased risk of military separation.

CONCLUSIONS

Prevalence of alcohol misuse was high among military families. Service member alcohol misuse was more strongly related to military separation than spouse alcohol misuse. Additionally, heavy weekly drinking among female service members may be an indicator of a significant issue that merits interventions aimed at retaining these service members.

Respiratory Health after Military Service in Southwest Asia and Afghanistan. An Official American Thoracic Society Workshop Report

Since 2001, more than 2.7 million U.S. military personnel have been deployed in support of operations in Southwest Asia and Afghanistan. Land-based personnel experienced elevated exposures to particulate matter and other inhalational exposures from multiple sources, including desert dust, burn pit combustion, and other industrial, mobile, or military sources. A workshop conducted at the 2018 American Thoracic Society International Conference had the goals of: 1) identifying key studies assessing postdeployment respiratory health, 2) describing emerging research, and 3) highlighting knowledge gaps. The workshop reviewed epidemiologic studies that demonstrated more frequent encounters for respiratory symptoms postdeployment compared with nondeployers and for airway disease, predominantly asthma, as well as case series describing postdeployment dyspnea, asthma, and a range of other respiratory tract findings. On the basis of particulate matter effects in other populations, it also is possible that deployers experienced reductions in pulmonary function as a result of such exposure. The workshop also gave particular attention to constrictive bronchiolitis, which has been reported in lung biopsies of selected deployers. Workshop participants had heterogeneous views regarding the definition and frequency of constrictive bronchiolitis and other small airway pathologic findings in deployed populations. The workshop concluded that the relationship of airway disease, including constrictive bronchiolitis, to exposures experienced during deployment remains to be better defined. Future clinical and epidemiologic research efforts should address better characterization of deployment exposures; carry out longitudinal assessment of potentially related adverse health conditions, including lung function and other physiologic changes; and use rigorous histologic, exposure, and clinical characterization of patients with respiratory tract abnormalities.

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.

Mental health, physical health, and health-related behaviors of U.S. Army Special Forces

Objectives

To prospectively examine the health and health-related behaviors of Army Special Forces personnel in comparison with two distinct, but functionally similar Army groups.

Methods

Special Forces, Ranger Qualified, and General Purposes Forces enrolled in the Millennium Cohort Study were identified using data from the Defense Manpower Data Center. Using prospective survey data (2001–2014), we estimated the association of Army specialization with mental health, social support, physical health, and health-related behaviors with multivariable regression models.

Results

Among the 5,392 eligible participants (84.4% General Purposes Forces, 10.0% Special Forces, 5.6% Ranger Qualified), Special Forces personnel reported the lowest prevalence of mental disorders, physical health problems, and unhealthy behaviors. In the multivariable models, Special Forces personnel were less likely to report mental health problems, multiple somatic symptoms, and unhealthy behaviors compared with General Purpose Forces infantrymen (odds ratios [OR]: 0.20–0.54, p-values < .01). Overall, Special Forces personnel were similar in terms of mental and physical health compared with Ranger Qualified infantrymen, but were less likely to sleep < 5 hours/night (OR: 0.60, 95% confidence intervals: 0.40, 0.92) and have 5 or more multiple somatic symptoms (OR: 0.69, 95% CI: 0.49, 0.98). Both Special Forces personnel and Ranger Qualified infantrymen engaged in more healthy behaviors compared with General Purpose Forces infantrymen (OR: 2.57–6.22, p-values<0.05). Engagement in more healthy behaviors reduced the odds of subsequent adverse health outcomes, regardless of specialization.

Conclusions

Army Special Forces personnel were found to be mentally and physically healthier than General Purpose Forces infantrymen, which may in part be due to their tendency to engage in healthy behaviors. Findings indicate that engagement in a greater number of healthy behaviors may reduce odds for subsequent adverse outcomes.

Military Life Stressors, Family Communication and Satisfaction: Associations with Children's Psychosocial Outcomes

Families experience multiple stressors as a result of military service. The purpose of this study was to examine facets of military life and family factors that may impact child psychosocial and mental health functioning. Using baseline data from the Millennium Cohort Family Study, this study examined family demographics and composition (age, number of children), military life stressors (injury, family, and deployment stressors), family communication and satisfaction as assessed by the Family Adaptability and Cohesion Evaluation Scale-IV, parental social functioning assessed via the Short Form Health Survey-36, and child mental health and behavioral functioning (parental reports of clinician-diagnosed mental health conditions such as depression) and an adapted version of the Strengths and Difficulties Questionnaire. Injury- and family-related military stressors were significant indicators of heightened risk for child mental health conditions, whereas greater levels of parental social functioning and family satisfaction were associated with lower risk of child mental health conditions. Differential associations were found in child functioning when military-related variables (e.g., service component), sociodemographic, and family composition factors (number and age of the children in the home) were examined. These findings underscore the importance of examining the "whole child" within the broader ecological and military family context to understand factors associated with children's mental and behavioral health. The results from the present study highlight the complex relationships that may be at play, which, in turn, have considerable implications for the development of policies to support children and families encountering multiple stressors related to a parent's military service.