Epidemiologic Measures for Quantifying the Incidence of Concussion in National Collegiate Athletic Association Sports.

CONTEXT Injury rates compare the relative frequency of sport-related concussions across groups. However, they may not be intuitive to policy makers, parents, or coaches in understanding the likelihood of concussion. OBJECTIVE To describe 4 measures of incidence (athlete-based rate, athlete-based risk, team-based rate, and team-based risk) during the 2011-2012 through 2014-2015 academic years. DESIGN  Descriptive epidemiology study. SETTING Aggregate injury and exposure data collected from the National Collegiate Athletic Association Injury Surveillance Program in 13 sports (men's baseball, basketball, football, ice hockey, lacrosse, soccer, and wrestling and women's basketball, ice hockey, lacrosse, soccer, softball, and volleyball). PATIENTS OR OTHER PARTICIPANTS Collegiate student-athletes. MAIN OUTCOME MEASURE(S) Sport-related concussion data from the National Collegiate Athletic Association Injury Surveillance Program during the 2011-2012 through 2014-2015 academic years were analyzed. We calculated concussion rates per 1000 athlete-exposures (AEs), concussion risk, average number of concussions per team, and percentage of teams with at least 1 concussion. RESULTS During the 2011-2012 through 2014-2015 academic years, 1485 concussions were sustained by 1410 student-athletes across 13 sports. Concussion rates ranged from 0.09/1000 AEs in men's baseball to 0.89/1000 AEs in men's wrestling. Concussion risk ranged from 0.74% in men's baseball to 7.92% in men's wrestling. The average ± SD number of concussions per team ranged from 0.25 ± 0.43 in men's baseball to 5.63 ± 5.36 in men's football. The percentage of teams with a concussion ranged from 24.5% in men's baseball to 80.6% in men's football. CONCLUSIONS   Although men's wrestling had a higher concussion rate and risk, men's football had the largest average number of concussions per team and the largest percentage of teams with at least 1 concussion. The risk of concussion, average number of concussions per team, and percentage of teams with concussions may be more intuitive measures of incidence for decision makers. Calculating these additional measures is feasible within existing injury surveillance programs, and this method can be applied to other injury types.