The Association between Altitude and Concussion Injury Rates in College Football

Abstract

Participating in sports at high altitude may have a protective effect on the brain according to research studies. High school and professional football players in two separate studies had lower odds of sustaining a concussion when playing at higher altitudes. These studies employed potentially unreliable public data sources to identify injury events. Research using validated data collection methods may better estimate the association between concussion injury risk and altitude. PURPOSE: To determine the association between concussion injury rates and altitude (high and low) during college football games. METHODS: Athletic trainers from 21 Division I football programs provided game exposure and injury data to the National Collegiate Athletic Association Injury Surveillance Program during the 2009/10 to 2013/14 academic years. Stadium locations for all games during these 63 team-seasons were obtained from college athletic department websites. Corresponding elevations in meters for each stadium at field level were gathered from Google Earth. Concussion rates per 1000 athlete-exposures (AE) were compared in two ways based on our sample of stadium elevations: 1) by median split (elevation >178m vs. elevation <178m); and 2) by quartile split (highest: >284m vs. lowest: <49m). These comparisons are reported as rate ratios (RR) and 95% confidence intervals (CI). RESULTS: In the study period, 169 concussions were reported over 49,040 game AE (3.45/1000 AE). The concussion injury rate was greatest at higher elevations. Using a median split, the concussion injury rate above 178m (4.18/1000 AE) was 1.47 times the injury rate below 178m (2.84/1000 AE; 95% CI for RR: 1.09 to 2.00; p=0.01). The concussion rate at the highest elevations (>284m; 5.01/1000 AE) was 1.67 times higher than the rate at the lowest elevations (<49m; 3.00/1000 AE; 95% CI for RR: 1.13 to 2.48; p=0.01). CONCLUSION: Our findings contrast previous research. College football game concussion injury rates increase at higher altitude. These findings warrant further research on the possible neurophysiological mechanisms that may be affected by stadium elevation and their relationship to concussion injury risk. Given the varied elevations of sporting venues globally, this and future studies may have a global health impact.