Incidence of Traumatic Brain Injury in the U.S. Military, 2010-2014.

Introduction: Traumatic brain injury (TBI) is a significant health issue that affects U.S. military service members (SM) at home and in combat deployments. We estimated the TBI incidence rate in the deployed and non-deployed setting between 2010 and 2014 and identified subgroups with elevated rates for prevention efforts.

Methods: Retrospective population-based study of all active duty U.S. military SM that sustained a first active duty TBI diagnosis between January 2010 and December 2014 collected and analyzed in 2017. Using Armed Forces Health Surveillance Branch data we calculated the Mantel-Haenszel (MH) standardized TBI incidence rate in the deployed and non-deployed setting, adjusting for service and demographic factors.

Results: From 2010 to 2014, the MH standardized incidence rate for deployed SMs was 3,265 TBIs per 100 thousand p-yrs (95% CI: 3,222-3,307) and 1,705.2 (95% CI: 1,694.0-1,716.5) for non-deployed SMs. The youngest deployed male Army soldiers, those ages 17-24, especially White and Hispanic soldiers, had the highest TBI incidence rate (IR) of 5,748.7 (95% CI: 5,585.8-5,916.4) and 5,010.3 (95% CI: 4,647.5-5,401.4), respectively. The IR for all branches was 1,972.6 (95% CI: 1,959.5-1,985.7) and 724.0 (95% CI: 714.9-733.0) for Reserve/Guard Service members.

Conclusions: Across all years, Marines and Army Soldiers experience the highest rates of injury with deployed SMs having elevated IRs of TBI. The TBI IR among deployed SMs was 91% higher than among those in the non-deployed setting, due to continued exposures to combat. Deployed Reserve/Guard component SMs seem to have an above average rate, a finding with implications for training and prevention.