Does the apolipoprotein ε4 allele predispose varsity athletes to concussion?: A prospective cohort study

Objective: To determine the association between the apolipoprotein epsilon 4 allele and concussion. We hypothesized that apolipoprotein epsilon 4 carriers may be more likely to sustain a concussion. Design: Prospective cohort study. Setting: University of Toronto varsity athletics. Participants: Included 318 of 822 collegiate student athletes who participated in University of Toronto varsity sports from September 2002 to April 2006. Assessment of Risk Factors: The presence of apolipoprotein EA was described dichotomously after genotyping blood samples collected from participants. Main Outcome Measurements: Concussions were identified by sport-medicine professionals present on the sidelines using on-field assessment forms. All concussion diagnoses were verified by a sports medicine physician. Survival analysis was used to determine the association between apolipoprotein epsilon 4 and first concussion. Results: The unadjusted hazard ratio for concussion in the apolipoprotein FA carriers was 1.18 (95% CI: 0.52, 2.69) compared to noncarriers. Adjustment for sex, weight, height, and team type resulted in a hazard ratio of 1.06 (95% Cl: 0.41, 2.72), indicating little effect from confounding factors. Conclusions: There is no important association between carrying the apolipoprotein epsilon 4 allele and sustaining a concussion. At this time, we do not recommend preseason genetic testing for varsity. athletes as a mechanism for targeting prevention strategies.