Abstract
OBJECTIVE: Although traumatic brain injury (TBI) has been identified as a risk factor for suicide among individuals from civilian and military cohorts, less is known about suicidal ideation (SI) and suicide attempts (SA), which often predate suicide. Moreover, little work has been conducted to evaluate sex-based differences. DATA SOURCES: Department of Defense, Military Health System (MHS), and Department of Veterans Affairs, Corporate Data Warehouse. PARTICIPANTS: Active Duty military service members (SM) with a history of TBI in the MHS (January 2000-March 2022); overall cohort with sex in medical record n = 354 972, males n = 305 284, and females n = 49 688. DESIGN: Descriptive retrospective observational study. MAIN MEASURES: In the MHS, index TBIs were identified via diagnostic codes. SI and SA codes were captured: (1) prior to index TBI; and (2) within 1, 2, and 5 years post-index TBI; total and newly identified. Sex was identified using MHS data. RESULTS: Most injuries sustained by males and females were mild, 65.9% and 77.2%, respectively. Post-TBI incidence of SI and SA was higher than the prevalence of these diagnoses prior to TBI. At all post-TBI time points, the risk of SI and SA was significantly higher for females compared to males. The risk ratio (RR; females:males) at 1-year post-TBI was 1.59 (95% confidence interval [CI]: 1.48, 1.70) and 2.66 (95% CI: 2.06, 3.43), for SI and SA, respectively. Risk remained higher for females through 5-year post-TBI with SI RR = 1.20 (95% CI: 1.13, 1.26) and SA RR = 1.94 (95% CI: 1.58, 2.37). CONCLUSIONS: Findings highlight the risk of SI and SA by female and male SMs post-index TBI, with female SMs being at higher risk than males, as well as the need for suicide risk screening for those with a history of TBI. Implementing screening in settings where females commonly receive care should be considered.