Epidemiology of sudden death in organized school sports in Japan
Background: Nearly half of the sudden deaths documented in Japanese middle and high school occurred during school organized sport activities. However, no study to date has calculated the incidence rates of these deaths by sport. Therefore, this study aimed to describe the epidemiology of sudden death in organized school sports in Japan. Methods: Data submitted to Japan Sport Council (JSC) Injury and Accident Mutual Aid Benefit System between 2005 and 2016 were retrieved from JSC website for analysis (n = 1137). Case information on fatal incidents that occurred during organized school sports in middle and high school students were extracted for analysis (n = 198). Descriptive statistics about activity type, sex, sport, cause of death, and presence of on-site trained medical personnel were calculated using frequencies and proportions. Sudden death incidence rates were expressed per 100,000 athlete-years with 95% confidence intervals (CI). Results: The overall incidence rate of sports-related death was 0.38 deaths per 100,000 athlete-years (95%CI = 0.30, 0.45). Only three cases (2%) reported having trained medical personnel on-site at the time of death. Most deaths were in male student athletes (n = 149/162, 92%), with 7.5 times greater fatality rate in male compared to female student athletes (incidence rate ratio, 7.5; 95%CI = 4.43, 13.22). Baseball (n = 25/162, 15.4%), judo (n = 24/162, 14.8%), soccer/futsal (n = 20/162, 12.3%), and basketball (n = 18/162, 11.1%) accounted for 53.7% of deaths. Accounting for the number of participants in the respective sport, the three highest average incident rates of death were reported in rugby (4.59 deaths per 100,000 athlete-years, 95%CI = 2.43, 6.75), judo (3.76 deaths per 100,000 athlete-years, 95%CI = 1.58, 5.93), and baseball (0.59 deaths per 100,000 athlete-years, 95%CI = 0.38, 0.79). The top three causes of death were sudden cardiac arrest (n = 68/162, 42.0%), head trauma (n = 32/162, 19.8%), and heat related injury (n = 25/162, 15.4%). Conclusions: In conclusion, the highest rates of sports-related death among Japanese student athletes were observed in the following: rugby, male athletes, and during practices. The leading cause of death was sudden cardiac arrest.