Sex and occupation are salient factors associated with lateral ankle sprain risk in military tactical athletes

Objectives: To assess the risk of lateral ankle sprain (LAS) in male and female tactical athletes across different military occupations in the US military. Design: Retrospective cohort. Methods: The Defense Medical Epidemiology Database was queried for the number of individuals with ICD-9 diagnosis codes 845.00 (sprain of ankle, unspecified) and 845.02 (calcaneofibular ligament sprain) on their initial encounter from 2006 to 2015. Relative risk (RR) and chi-square statistics were calculated assessing sex and occupational category on LAS risk. Results: 272,970 enlisted males (27.9 per 1000 person-years), 56,732 enlisted females (34.5 per 1000 person-years), 24,534 male officers (12.6 per 1000 person-years), and 6020 female officers (16.4 per 1000 person-years) incurred a LAS. Enlisted females in all occupational groups were at significantly higher risk for LAS than their male counterparts (RR 1.09–1.68; p < 0.001), except for Engineers (p = 0.15). Female officers had consistently higher risk for LAS in all occupational groups (RR 1.10–1.42; p < 0.001) compared with male officers, except Ground/Naval Gunfire (p = 0.23). Contrasted with Infantry, enlisted tactical athletes in the Special Operations Forces, Mechanized/Armor, Aviation, Maintenance, and Maritime/Naval Specialties were at lower risk (RR 0.38−0.93; p < 0.001), Artillery, Engineers, and Logistics Specialties were at higher risk (RR 1.04–1.18; p < 0.001), and Administration, Intelligence, and Communications were no different (p = 0.69). Compared with Ground/Naval Gunfire officers, Aviation officers were at significantly lower risk (RR, 0.75; p < 0.001), and Engineers, Maintenance, Administration, Operations/Intelligence, and Logistics officers were at higher risk (RR, 1.08–1.20; p < 0.001). Conclusions: Sex and military occupation were salient factors associated with LAS risk.