Identifying Predictors of Positive and Negative Affect at Mid-Deployment Among Military Medical Personnel.

INTRODUCTION: Positive and negative affect influence an individual's ability to utilize available physical, psychological, and social resources to maximize responses to life events. Little research has examined the factors that influence the development of positive affect or reduction of negative affective responses among deployed military personnel. The present study aimed to investigate the relationship between deployment-related stressors and symptoms of behavioral health concerns with affectivity among deployed U.S. service members. MATERIALS AND METHODS: Participants were 1148 U.S. Air Force medical personnel deployed to Balad, Iraq, between 2004 and 2011. All participants completed self-report measures of PTSD symptoms, general military and combat exposure, stress, and affectivity. The Institutional Review Board at Wilford Hall Medical Center, the Air Force Personnel Survey Program, and the U.S. Army's Joint Combat Casualty Research Team reviewed and approved the study. RESULTS: Most respondents (89%, 1,018/1,139) reported a positive military experience, but many respondents reported exposure to a potentially traumatic event during deployment. For example, seeing dead or seriously injured Americans (47%, 523/1,123) was the most common exposure reported by participants. A large portion of personnel (21%, 232/1,089) reported clinical levels of PTSD symptoms (score of 33 or higher on the Posttraumatic Stress Disorder Checklist-Military version). Risk factors, including PTSD symptoms, combat exposure, and stress, explained 39% of the variance in negative affect, R2 = 0.39, F(1046) = 224.96, P < .001. Conversely, these risk and resilience factors, including PTSD symptoms, combat exposure, stress, and general military experiences, explained 28% of the variance in positive affect, R2 = 0.28, F(1050) = 103.79, P < .001. No significant gender differences were found between models predicting positive and negative affect. CONCLUSIONS: Negative mood states may be partly an epiphenomenon of PTSD, which has been shown to be safely and effectively treated in the deployed environment. Social support during deployments is uniquely associated with a positive mood. These findings extend beyond the military and into any high-stress occupation wherein leaders could interpret these findings as a need to build or reinforce efforts to provide opportunities to sustain healthy relationships in personnel. These critical indigenous resources support mission readiness and enable the maintenance of positive psychological health.

Disease and Non-Battle Injury in Deployed Military: A Systematic Review and Meta-analysis.

INTRODUCTION: Disease and non-battle injury (DNBI) has historically been the leading casualty type among service members in warfare and a leading health problem confronting military personnel, resulting in significant loss of manpower. Studies show a significant increase in disease burden for DNBI when compared to combat-related injuries. Understanding the causes of and trends in DNBI may help guide efforts to develop preventive measures and help increase medical readiness and resiliency. However, despite its significant disease burden within the military population, DNBI remains less studied than battle injury. In this review, we aimed to evaluate the recently published literature on DNBI and to describe the characteristics of these recently published studies. MATERIALS AND METHODS: This systematic review is reported in the Prospective Register of Systematic Reviews database. The systematic search for published articles was conducted through July 21, 2022, in Cumulative Index of Nursing and Allied Health, Cochrane Library, Defense Technical Information Center, Embase, and PubMed. Guided by the Preferred Reporting Items for Systematic Reviews and Meta-analyses, the investigators independently screened the reference lists on the Covidence website (covidence.org). An article was excluded if it met any of the following criteria: (1) Published not in English; (2) published before 2010; (3) data used before 2001; (4) case reports, commentaries, and editorial letters; (5) systematic reviews or narrative reviews; (6) used animal models; (7) mechanical or biomechanical studies; (8) outcome was combat injury or non-specified; (9) sample was veterans, DoD civilians, contractors, local nationals, foreign military, and others; (10) sample was U.S. Military academy; (11) sample was non-deployed; (12) bioterrorism study; (13) qualitative study. The full-text review of 2 independent investigators reached 96% overall agreement (166 of 173 articles; κ = 0.89). Disagreements were resolved by a third reviewer. Study characteristics and outcomes were extracted from each article. Risk of bias was assessed using the Newcastle-Ottawa Scale. Meta-analysis of pooled estimates of incidence rates for disease (D), non-battle injury (NBI), and combined DNBI was created using random-effects models. RESULTS: Of the 3,401 articles, 173 were included for the full review and 29 (16.8%) met all inclusion criteria. Of the 29 studies included, 21 (72.4%) were retrospective designs, 5 (17.2%) were prospective designs, and 3 (10.3%) were surveys. Across all studies, the median number of total cases reported was 1,626 (interquartile range: 619.5-10,203). The results of meta-analyses for 8 studies with reported incidence rates (per 1,000 person-years) for D (n = 3), NBI (n = 7), and DNBI (n = 5) showed pooled incidence rates of 22.18 per 1,000 person-years for D, 19.86 per 1,000 person-years for NBI, and 50.97 per 1,000 person-years for combined DNBI. Among 3 studies with incidence rates for D, NBI, and battle injury, the incidence rates were 20.32 per 1,000 person-years for D, 6.88 per 1,000 person-years for NBI, and 6.83 per 1,000 person-years for battle injury. CONCLUSIONS: DNBI remains the leading cause of morbidity in conflicts involving the U.S. Military over the last 20 years. More research with stronger designs and consistent measurement is needed to improve medical readiness and maintain force lethality. LEVEL OF EVIDENCE: Systematic Review and Meta-Analysis, Level III.

Enhancing the Management of Deployment-Limiting Medical Conditions in the U.S. Department of Navy Leveraging Electronic Health Records and Predictive Analytics Methods.

INTRODUCTION: Deployment-limiting medical conditions (DLMCs) such as debilitating injuries and conditions may interfere with the ability of military service members (SMs) to deploy. SMs in the United States (U.S.) Department of the Navy (DoN) with DLMCs who are not deployable should be placed in the medically restricted status of limited duty (LIMDU) or referred to the Physical Evaluation Board (PEB) for Service retention determination. It is critical to identify SMs correctly and promptly with DLMCs and predict their return-to-duty (RTD) to ensure the combat readiness of the U.S. Military. In this study, an algorithmic approach was developed to identify DoN SMs with previously unidentified DLMCs and predict whether SMs on LIMDU will be able to RTD. MATERIALS AND METHODS: Five years of historical data (2016-2022) were obtained from inpatient and outpatient datasets across direct and purchased care from the Military Health System (MHS) Data Repository (MDR). Key fields included International Classification of Diseases diagnosis and procedure codes, Current Procedure Terminology codes, prescription medications, and demographics information such as age, rank, gender, and service. The data consisted of 44,580,668 medical encounters across 1,065,224 SMs. To identify SMs with unidentified DLMCs, we developed an ensemble model combining outputs from multiple machine learning (ML) algorithms. When the ML ensemble model predicted a SM to have high risk scores, despite appearing healthy on administrative reports, their case was reviewed by expert clinicians to investigate for previously unidentified DLMCs; and such feedback served to validate the developed algorithms. In addition, leveraging 1,735,422 encounters (60,433 SMs) from LIMDU periods, we developed four separate ML models to estimate RTD probabilities for SMs after each medical encounter and predict the final LIMDU outcome. RESULTS: The ensemble model had 0.91 area under the receiver operating characteristic curve (AUROC). Out of 236 (round one) and 314 (round two) SMs reviewed by clinicians, 127 (54%) and 208 (66%) SMs were identified with a previously unidentified or undocumented DLMC, respectively. Regarding predicting RTD for SMs placed on LIMDU, the best performing ML model achieved 0.76 AUROC, 68% sensitivity, and 71% specificity. CONCLUSION: Our research highlighted potential benefits of using predictive analytics in a medical assessment to identify SMs with DLMCs and to predict RTD outcomes once placed on LIMDU. This capability is being deployed for real-time clinical decision support to enhance health care provider's deployability assessment capability, improve accuracy of the DLMC population, and enhance combat readiness of the U.S Military.

Morbidity burdens attributable to various illnesses and injuries among deployed active and reserve component service members of the U.S. Armed Forces, 2023.

This report updates previous analyses of health care burden distributions among active and reserve component service members of the U.S. Armed Forces in deployed settings. Musculoskeletal disorders in combination with administrative and other health services (ICD-10 "Z" codes) accounted for more than half of all medical encounters in 2023 among service members deployed to the U.S. Central Command (CENTCOM) and Africa Command (AFRICOM). Three common injury conditions occurred among male and female service members deployed to U.S. CENTCOM and U.S. AFRICOM: other back problems, arm and shoulder injuries, and knee injuries.

Medical evacuations out of U.S. Central and Africa commands among the active and reserve components of the U.S. Armed Forces, 2023

This report summarizes the nature, numbers, and trends of conditions for which military members were medically evacuated from the U.S. Central Command (CENTCOM) or Africa Central Command (AFRICOM) operations during 2023, with historical comparisons to the previous 4 years. Mental health disorders and injuries were the most common diagnostic categories in 2023 among service members medically evacuated from U.S. Central Command (CENTCOM) and U.S. Africa Command (AFRICOM). In 2023, 724 service members were medically evacuated from CENTCOM and 225 were evacuated from AFRICOM, with hospitalization required for 197 (27.2%) and 50 (22.2%), respectively. Most service members who were medically evacuated from CENTCOM or AFRICOM were returned to full duty status following their post-evacuation hospitalizations or outpatient evaluations. In 2023, evacuations for both battle and non-battle injuries from U.S. CENTCOM increased, following a period of decline. The number of service members medically evacuated in 2023 from AFRICOM remained unchanged from the previous year.

Symptoms of Posttraumatic Stress Disorder Among Japanese Peacekeepers Deployed in South Sudan.

Importance: Peacekeepers in United Nations missions experience potentially traumatic events, resulting in increased risk for posttraumatic stress disorder (PTSD). Understanding the course and risk factors of PTSD symptom severity is crucial to ensure personnel safety. Objective: To investigate the incidence of PTSD, symptom severity trajectories, and potential risk factors associated with adverse trajectories among Japanese peacekeepers deployed in South Sudan. Design, Setting, and Participants: Data for this 6-year prospective cohort study were collected from December 2011 to December 2018 from Japan Ground Self-Defense Force personnel deployed at the United Nations Mission in South Sudan, corresponding to before and up to 78 months after deployment. Of 3799 potential participants, 80 were excluded because of multiple deployments and 757 because of missing data, incomplete responses, or not providing informed consent. Therefore, 2962 participants were included in the analysis. Data analysis was performed from February 2022 to February 2024. Exposure: The participants were deployed to United Nations Mission in South Sudan for 6 months. Main Outcomes and Measures: The 22-item Impact of Event Scale-Revised was used to assess PTSD symptoms, with 25 or more points indicating probable PTSD (p-PTSD). Sociodemographic data were collected, and the 30-item General Health Questionnaire was administered before deployment to identify risk factors for PTSD symptom severity. Results: In the 2962 participants studied (2901 [97.9%] male; mean [SD] age, 33.9 [7.2] years), the incidence of p-PTSD was 3.95%. Latent growth mixture models identified 4 symptom severity trajectories: resilient (2143 [72.3%]), recovery (479 [16.2%]), protracted (182 [6.1%]), and delayed (158 [5.3%]). Multinomial logistic regression showed that sleep disturbance was a common risk factor for the 2 most severe trajectories (protracted: odds ratio [OR], 1.29; 95% CI, 1.08-1.54; delayed: OR, 1.26; 95% CI, 1.03-1.53), whereas older age (OR, 1.25; 95% CI, 1.06-1.48), anxiety and dysphoria (OR, 1.45; 95% CI, 1.20-1.75), and general illness (OR, 1.30; 95% CI, 1.06-1.59) were associated with the protracted trajectory. Conclusions and Relevance: This cohort study found that approximately 4% of the participants developed p-PTSD and identified 4 distinct PTSD symptom trajectories. The findings suggest that addressing sleep disturbance and general health issues could effectively prevent PTSD symptoms among peacekeepers.

Deployment-related toxic exposures are associated with worsening mental and physical health after military service: Results from a self-report screening of veterans deployed after 9/11.

Exposure to toxins-such as heavy metals and air pollution-can result in poor health and wellbeing. Recent scientific and media attention has highlighted negative health outcomes associated with toxic exposures for U.S. military personnel deployed overseas. Despite established health risks, less empirical work has examined whether deployment-related toxic exposures are associated with declines in mental and physical health after leaving military service, particularly among the most recent cohort of veterans deployed after September 11, 2001. Using data from 659 U.S. veterans in the VISN 6 MIRECC Post-Deployment Mental Health Study, we tested whether self-reported toxic exposures were associated with poorer mental and physical health. At baseline, veterans who reported more toxic exposures also reported more mental health, ß = 0.14, 95% CI [0.04, 0.23], p = 0.004, and physical health symptoms, ß = 0.21, 95% CI [0.11, 0.30], p < 0.001. Over the next ten years, veterans reporting more toxic exposures also had greater increases in mental health symptoms, ß = 0.23, 95% CI [0.15, 0.31], p < 0.001, physical health symptoms, ß = 0.22, 95% CI [0.14, 0.30], p < 0.001, and chronic disease diagnoses, ß = 0.15, 95% CI [0.07, 0.23], p < 0.001. These associations accounted for demographic and military covariates, including combat exposure. Our findings suggest that toxic exposures are associated with worsening mental and physical health after military service, and this recent cohort of veterans will have increased need for mental health and medical care as they age into midlife and older age.

Deployment to Military Bases With Open Burn Pits and Respiratory and Cardiovascular Disease.

Importance: Many veterans who served in Afghanistan and Iraq during Operations Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) were deployed to military bases with open burn pits and exposed to their emissions, with limited understanding of the long-term health consequences. Objective: To determine the association between deployment to military bases where open burn pits were used for waste disposal and the subsequent risk of developing respiratory and cardiovascular diseases. Design, Setting, and Participants: This retrospective observational cohort study used Veterans Health Administration medical records and declassified deployment records from the Department of Defense to assess Army and Air Force veterans who were deployed between 2001 and 2011 and subsequently received health care from the Veterans Health Administration, with follow-up through December 2020. Data were analyzed from January 2023 through February 2024. Exposure: Duration of deployment to military bases with open burn pits. Main Outcomes and Measures: Diagnosis of asthma, chronic obstructive pulmonary disease, interstitial lung disease, hypertension, myocardial infarction, congestive heart failure, ischemic stroke, and hemorrhagic stroke. Results: The study population included 459 381 OEF and OIF veterans (mean [SD] age, 31.6 [8.7] years; 399 754 [87.0%] male). Median (IQR) follow-up from end of deployment was 10.9 (9.4-12.7) years. For every 100 days of deployment to bases with burn pits, veterans experienced increased adjusted odds for asthma (adjusted odds ratio [aOR], 1.01; 95% CI, 1.01-1.02), chronic obstructive pulmonary disease (aOR, 1.04; 95% CI, 1.02-1.07), hypertension (aOR, 1.02; 95% CI, 1.02-1.03), and ischemic stroke (aOR, 1.06; 95% CI, 0.97-1.14). Odds of interstitial lung disease, myocardial infarction, congestive heart failure, or hemorrhagic stroke were not increased. Results based on tertiles of duration of burn pit exposures were consistent with those from the continuous exposure measures. Conclusions and Relevance: In this cohort study, prolonged deployment to military bases with open burn pits was associated with increased risk of developing asthma, COPD, and hypertension. The results also point to a possible increased risk in ischemic stroke. The novel ability to use integrated data on deployment and health outcomes provides a model for additional studies of the health impact of environmental exposures during military service.

Sex Differences in Postinjury Health Profiles Among U.S. Military Personnel Following Deployment-Related Concussion.

Background: Women in the U.S. military are now authorized to serve in direct combat occupations. This may increase their risk of combat injuries, such as concussion, in future conflicts. Knowledge of sex differences in health profiles after concussion is paramount for military medical planning efforts. The purpose of this study was to assess sex-related differences in health profiles among U.S. military personnel following deployment-related concussion. Materials and Methods: We conducted a retrospective study of service members who sustained a concussion during combat deployment between 2004 and 2013. Postinjury diagnoses were abstracted from outpatient encounters in electronic health records for 24 months after concussion. We used hierarchical clustering to identify clusters, termed "health profiles," and logistic regression to determine whether sex predicted membership in the health profiles. Results: The study sample included 346 women and 4536 men with deployment-related concussion. Five postinjury health profiles were identified and classified as no morbidity, back pain, tinnitus/memory loss, posttraumatic stress disorder/postconcussion syndrome, and multimorbidity. Women relative to men had higher odds of membership in the back pain (odds ratio [OR] = 1.32; 95% confidence interval [CI] = 1.05-1.67) and multimorbidity profiles (OR = 1.44; 95% CI = 1.03-2.00) and lower odds than men in the tinnitus/memory loss profile (OR = 0.62; 95% CI = 0.42-0.91). Conclusions: Postinjury health profiles among U.S. service members differ by sex following deployment-related concussion, particularly with a higher burden of multimorbidity among women than men, which may require interdisciplinary care. Women also had higher odds of membership in the back pain profile and lower odds in the tinnitus/memory loss profile than men. To prepare for future military operations where women may have greater exposure to combat, continued research elucidating health-related sex differences after deployment-related concussion is imperative.

United States Army Reserve/National Guard soldiers' healthcare experiences, attitudes, and preferences: Differences based on deployment status.

Some United States Army Reserve/National Guard (USAR/NG) soldiers have substantial health needs, which may be service-related, but not necessarily resulting from deployment. However, most USAR/NG members need to have been deployed to qualify for Veterans Administration (VA) benefits. Therefore, many USAR/NG soldiers seek care from civilian healthcare providers (HCPs). Using a subset (N = 430 current/former soldiers) of Operation: SAFETY study data, we used regression models to examine differences in healthcare experiences, attitudes, and preferences by deployment status (never-deployed vs. previously-deployed). Final models controlled for age, sex, rank (enlisted vs. officer), military status (current vs. former military), and RAND SF-36 General Health Score. Over 40% of soldiers agreed that civilian HCPs should ask patients about their military service, but never-deployed soldiers were less likely to report being asked about their service (p < 0.05) or how their service affects their health (p < 0.10). Never-deployed soldiers were also less likely to attribute their health concerns to military service (p < 0.001). Although never-deployed soldiers were more likely to prefer receiving physical (p < 0.05) and mental (p < 0.05) healthcare outside of the VA than previously-deployed soldiers, never-deployed soldiers had low confidence in their HCP's understanding of their needs (49% thought that their civilian HCP did not understand them; 71% did not think that their civilian HCP could address military-related health concerns; 76% thought that their civilian HCP did not understand military culture). Findings demonstrate that although civilian HCPs may be the preferred (and only) choice for never-deployed USAR/NG soldiers, they may need additional support to provide care to this population.