Apolipoprotein E Genotype and Concussion in College Athletes

Objective: To evaluate the association between apolipoprotein E (APOE) polymorphisms (E2, C/T Arg158Cys; E4, T/C Cys112Arg; and promoter, g-219t) and the history of concussion in college athletes. We hypothesized that carrying 1 or more APOE rare (or minor) allele assessed in this study would be associated with having a history of 1 or more concussions. Design: Multicenter cross-sectional study. Setting: University athletic facilities. Participants: One hundred ninety-six male football (n = 163) and female soccer (n = 33) college athletes volunteered. Interventions: Written concussion history questionnaire and saliva samples for genotyping. Main Outcome Measures: Self-reported history of a documented concussion and rare APOE genotype (E2, E4, promoter). Results: There was a significant association (Wald chi(2) = 3.82; P = 0.05; odds ratio = 9.8) between carrying all APOE rare alleles and the history of a previous concussion. There was also a significant association (Wald chi(2) = 3.96, P = 0.04, odds ratio = 8.4) between carrying the APOE promoter minor allele and experiencing 2 or more concussions. Conclusions: Carriers of all 3 APOE rare (or minor) alleles assessed in this study were nearly 10 times more likely to report a previous concussion and may be at a greater risk of concussion versus noncarriers. Promoter minor allele carriers were 8.4 times more likely to report multiple concussions and may be at a greater risk of multiple concussions versus noncarriers. Research involving larger samples of individuals with multiple concussions and carriers of multiple APOE rare alleles is warranted.