Does the apolipoprotein epsilon 4 allele predispose varsity athletes to concussion? A prospective cohort study

Abstract

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 epsilon 4 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 epsilon 4 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% CI: 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.