Use of Time-to-Event Analyses to Identify Concussion Prevention Opportunities During Athletic Seasons: Findings from The Ivy League-B1G Ten Epidemiology of Concussion Study

Background: We aim to create concussion prevention opportunities using time-to-event analytic approaches. This study investigates the timing of sport-related concussion (SRC) incidence across a full academic year. Method: In a prospective cohort study, The Ivy League-Big Ten Epidemiology of Concussion Study, we examined SRCs within contact and collision sports across the two conferences during 2023–2024 academic year. Survival analyses, using academic year start and end dates and dates of injury, investigated the timing of SRC onset in each sport. Kaplan-Meier curves and Cox proportional hazard models compared instantaneous risks using hazard ratios (HR) between men’s and women’s teams with 95% confidence intervals (CI). Results: Out of 4,555 contact and collision athletes in fall (n = 2,888, 63.4%), winter (n = 826, 18,1%), and spring (n = 841, 18.5%) sports, 369 SRCs occurred; 13 athletes sustained repeat SRCs during the academic year. Football (n = 155, 42.0%) and women’s soccer (n = 37, 10.0%) accounted for the largest percentages of SRCs. Across all sports, by 30 days 98.9%, 60 days 97.6%, 90 days 95.9%, and by end of the academic year 92.3% were free from concussion, respectively. Within-sport, SRC proportions were highest during weeks 2 and 15 in football, the middle of the season (week 6) in sprint football, the end of the fall season (week 12) in women’s rugby, and early in the season (week 13) in women’s ice hockey. By the end of the academic year the proportion free from SRC was 81.7% (95%CI: 72.3–88.2) to 95.6% (95%CI: 92.5–97.4). There was no association in SRC hazard between men and women overall, (HR:1.1, 95%CI:0.9,1.4), ice hockey (HR:1.3, 95%CI: 0.7, 2.6), soccer (HR:0.5, 95%CI:0.3,1.0), and lacrosse (HR:1.0, 95%CI:0.6,1.8). Conclusion: This is the first study examining SRC risk utilizing repeated time-to-event analyses to identify notable timeframes of SRC incidence. With this method, and a collaborative stakeholder-engaged prospective cohort study, it is possible to strategically direct SRC prevention efforts and advance analytic approaches, which was identified as a priority for future research at the most recent Concussion in Sport Group (CISG) meeting.