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.