Trends in concussion incidence in high school sports: a prospective 11-year study.

BACKGROUND Understanding the risk and trends of sports-related concussion among 12 scholastic sports may contribute to concussion detection, treatment, and prevention. PURPOSE To examine the incidence and relative risk of concussion in 12 high school boys' and girls' sports between academic years 1997-1998 and 2007-2008. STUDY DESIGN Descriptive epidemiology study. METHODS Data were prospectively gathered for 25 schools in a large public high school system. All schools used an electronic medical record-keeping program. A certified athletic trainer was on-site for games and practices and electronically recorded all injuries daily. RESULTS In sum, 2651 concussions were observed in 10 926 892 athlete-exposures, with an incidence rate of 0.24 per 1000. Boys' sports accounted for 53% of athlete-exposures and 75% of all concussions. Football accounted for more than half of all concussions, and it had the highest incidence rate (0.60). Girls' soccer had the most concussions among the girls' sports and the second-highest incidence rate of all 12 sports (0.35). Concussion rate increased 4.2-fold (95% confidence interval, 3.4-5.2) over the 11 years (15.5% annual increase). In similar boys' and girls' sports (baseball/softball, basketball, and soccer), girls had roughly twice the concussion risk of boys. Concussion rate increased over time in all 12 sports. CONCLUSION Although the collision sports of football and boys' lacrosse had the highest number of concussions and football the highest concussion rate, concussion occurred in all other sports and was observed in girls' sports at rates similar to or higher than those of boys' sports. The increase over time in all sports may reflect actual increased occurrence or greater coding sensitivity with widely disseminated guidance on concussion detection and treatment. The high-participation collision sports of football and boys' lacrosse warrant continued vigilance, but the findings suggest that focus on concussion detection, treatment, and prevention should not be limited to those sports traditionally associated with concussion risk.