Comparison of musculoskeletal injury and behavioral health diagnoses among United States Army active duty servicewomen in ground combat versus non-ground combat specialties: An update (2020-2023)

Abstract: INTRODUCTION: Historically, women in the U.S. Military have been prohibited from serving in ground combat occupational specialties (GCS) until the Secretary of Defense lifted the exclusion in January 2016, prompting studies into health outcomes for this new cohort. Phillips et al.(2016-2019) found that active duty servicewomen (ADSW) in GCS had lower odds of musculoskeletal injury (MSKI) and behavioral health (BH) diagnoses than peers in non-ground combat specialties (NGCS), likely because of a "healthy warrior" selection effect. With continued integration, cohort maturation, and factors such as the COVID-19 pandemic, this study updates MSKI and BH trends among ADSW from 2020 to 2023 and compares findings with the earlier cohort. MATERIALS AND METHODS: This retrospective cross-sectional study used data from the Military Health System Data Repository (MDR), including all ADSW (n = 77,568) who served from January 1, 2020, to December 31, 2023. Women in the Guard, Reserve, or with pregnancy diagnoses during or in the year prior were excluded. Primary outcomes-MSKI and BH diagnoses-were identified via ICD-10 codes. Adjusted odds ratios (AORs) and 95% CIs were calculated using multivariable logistic regression, comparing GCS vs. NGCS ADSW while adjusting for age, race & ethnicity, rank, and BMI. Two-sample z-tests assessed differences from Phillips et al.s 2016 to 2019 estimates. This study received an exempt determination from the Institutional Review Board at the Uniformed Services University of the Health Sciences. RESULTS: Of 77,568 ADSW, 5,024 (6.5%) served in GCS. Compared to NGCS, GCS women were younger (72.1% vs. 47.0% aged 18-23), more often enlisted (68.4% vs. 57.0%), and had lower obesity rates (8.4% vs. 12.6%), but higher rates of tobacco (7.7% vs. 7.6%), alcohol (7.9% vs. 6.7%), and substance use (2.5% vs. 1.9%). Adjusted analyses showed higher MSKI odds in GCS (AOR = 1.21, 95% CI: 1.13-1.30), a significant reversal from Phillips et al.(AOR = 0.86, 95% CI: 0.79-0.93; z = 6.01, P < .001). BH odds were lower in GCS (AOR = 0.83, 95% CI: 0.78-0.89), consistent with earlier findings (Phillips AOR = 0.87; 95% CI: 0.80-0.95). CONCLUSIONS: The increase in MSKI odds for GCS women contrasts sharply with prior findings, suggesting the dissipation of the initial selection effect as more women enter and remain in combat roles. This shift may reflect greater exposure duration, cumulative physical demands, or pandemic-era fitness disruptions. The continued lower BH odds in GCS, despite higher substance use, may reflect resilience, unit cohesion, or underreporting tied to stigma. These findings highlight the need for targeted, female-specific injury prevention and confidential, destigmatized mental health support as the Army moves toward sex-neutral standards in combat fitness.