title: Risk factors for concussive symptoms 1 week or longer in high school athletes.
abstract: OBJECTIVE
  To identify risk factors for concussive symptoms ≥1 week.
  
  
  METHODS
  Retrospective cohort study of concussions in the RIO™ database 2006-2009 (n = 1412) analysing risk factors for concussive symptoms ≥1 week. This study examined athlete's age, sex, weight, history of concussion, number of symptoms and specific symptoms. Data were stratified by football vs. non-football and analysed using Poisson regression to calculate relative risks and 95% confidence intervals.
  
  
  RESULTS
  Presenting with four or more symptoms was associated with double the risk for concussive symptoms ≥1 week for both football (95% CI = 1.3-3.5) and non-football players (95% CI = 1.4-4.6). History of prior concussion was associated with double the risk for concussive symptoms ≥1 week in football players only (95% CI = 1.3-3.5). Several symptoms were associated with concussive symptoms ≥1 week in all athletes: drowsiness, nausea and concentration difficulties. Sensitivity to light and noise was associated with concussive symptoms ≥1 week in non-football players only. Amnesia was associated with concussive symptoms ≥1 week in males, but not females. Loss of consciousness was not significant.
  
  
  CONCLUSIONS
  Risk factors for concussive symptoms ≥1 week are identifiable and can potentially be used to prognosticate for athletes and design evidence-based return-to-play guidelines.
authors.affiliation: Division of Adolescent Medicine, University of Washington, Seattle, USA. sara.chrisman@seattlechildrens.org
authors.forename: Sara P
authors.initials: SP
authors.lastname: Chrisman
authors.forename: Frederick P
authors.initials: FP
authors.lastname: Rivara
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Schiff
authors.forename: Chuan
authors.initials: C
authors.lastname: Zhou
authors.forename: R Dawn
authors.initials: RD
authors.lastname: Comstock
mesh_terms: D000293:Adolescent; D001265:Athletic Injuries / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology / Q000534:rehabilitation; D001835:Body Weight; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D038223:Post-Concussion Syndrome / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology / Q000534:rehabilitation; D011379:Prognosis; D020127:Recovery of Function; D012189:Retrospective Studies; D012307:Risk Factors; D012574:Schools; D017678:Sex Distribution; D014861:Washington / Q000453:epidemiology