title: 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.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  University of Toronto varsity athletics.
  
  
  METHODS
  Included 318 of 822 collegiate student athletes who participated in University of Toronto varsity sports from September 2002 to April 2006.
  
  
  METHODS
  The presence of apolipoprotein epsilon 4 was described dichotomously after genotyping blood samples collected from participants.
  
  
  METHODS
  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.
authors.affiliation: Department of Public Health Sciences, University of Toronto, Toronto, Ontario, Canada. vicki.kristman@uhnresearch.ca
authors.forename: Vicki L
authors.initials: VL
authors.lastname: Kristman
authors.forename: Charles H
authors.initials: CH
authors.lastname: Tator
authors.forename: Nancy
authors.initials: N
authors.lastname: Kreiger
authors.forename: Doug
authors.initials: D
authors.lastname: Richards
authors.forename: Lynda
authors.initials: L
authors.lastname: Mainwaring
authors.forename: Susan
authors.initials: S
authors.lastname: Jaglal
authors.forename: George
authors.initials: G
authors.lastname: Tomlinson
authors.forename: Paul
authors.initials: P
authors.lastname: Comper
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D053327:Apolipoprotein E4 / Q000235:genetics*; D001265:Athletic Injuries / Q000235:genetics*; D001924:Brain Concussion / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008297:Male; D011446:Prospective Studies; D013334:Students
chemical_list: D053327:Apolipoprotein E4