All-cause mortality risks among participants in mass-participation sporting events

Objectives Exercise transiently increases the risk for sudden death, whereas long-term exercise promotes longevity. This study assessed acute and intermediate-term mortality risks of participants in mass-participation sporting events.Methods Data of participants in Dutch running, cycling and walking events were collected between 1995 and 2017. Survival status was obtained from the Dutch Population Register. A time-stratified, case-crossover design examined if deceased participants more frequently participated in mass-participation sporting events 0-7 days before death compared with the reference period (14-21 days before death). Mortality risks during follow-up were compared between participants and non-participants from the general population using Cox regression.Results 546 876 participants (median (IQR) age 41 (31-50) years, 56% male, 72% runners) and 211 592 non-participants (41 (31-50) years, 67% male) were included. In total, 4625 participants died of which more participants had partaken in a sporting event 0-7 days before death (n=23) compared with the reference period (n=12), and the mortality risk associated with acute exercise was greater but did not reach statistical significance (OR 1.92; 95% CI 0.95 to 3.85). During 3.3 (1.1-7.4) years of follow-up, participants had a 30% lower risk of death (HR 0.70; 95% CI 0.67 to 0.74) compared with non-participants after adjustment for age and sex. Runners (HR 0.65; 95% CI 0.62 to 0.69) and cyclists (HR 0.70; 95% CI 0.64 to 0.77) had the best survival during follow-up followed by walkers (HR 0.88; 95% CI 0.80 to 0.94).Conclusion Participating in mass-participation sporting events was associated with a non-significant increased odds (1.92) of mortality and a low absolute event rate (4.2/100 000 participants) within 7 days post-event, whereas a 30% lower risk of death was observed compared with non-participants during 3.3 years of follow-up. These results suggest that the health benefits of mass sporting event participation outweigh potential risks.