Acute and Long-Term Mortality Rates among Participants of Mass-Participation Sport Events Versus the General Population

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The work of T.M.H.E is supported by the Netherlands Heart Foundation. Background Exercise training improves cardiovascular health and lowers the risk for morbidity and mortality. However, an acute bout of exercise transiently increases the risk for sudden death. It is unknown how participation in a mass-participation exercise event impacts mortality risk compared to non-participation. Purpose To assess the acute and long-term mortality risk among participants of mass-participation exercise events and to place these risks into perspective. Methods Data was collected among participants of Dutch running, cycling and long-distance walking events between 1995 and 2017. We retrieved age, sex, exercise type from the database of event organizers. The survival status and date of death were extracted from the Dutch Population Register (DPR). A time-stratified case-crossover design with an 8-day risk and reference period was used to examine if deceased athletes more frequently participated in mass-participation exercise events at 0 to 8 days before their death compared to the reference period (i.e., 14 to 21 weeks before death). Mixed-effects logistic regression was used to calculate the odds ratio (OR) with 95% confidence intervals (95% CI). We also retrieved controls (i.e., individuals not partaking in mass-participation exercise events) from the DPR (n=211,592) and compared long-term mortality risks between athletes and controls using stratified Kaplan-Meier curves and Cox regression models. Results 547,014 athletes (age 41 years [Q25 31; Q75 50], 56% male, 72% runners, 11% cyclists) and 211,592 controls (age 41 years [Q25 31; Q75 50], 67% male) were included in this study. Participation in mass-participation exercise events was higher at 0 to 8 days before death (i.e., risk period, n=23 deceased athletes) compared to 14 to 21 days before death (i.e., reference period, n=12 deceased athletes), but the mortality risk was not significantly elevated after participation in an exercise event (OR 1.92; 95%CI 0.95-3.85). During a median follow-up of 3.3 years [Q25 1.1; Q75 4.8], 4,625 (0.8%) athletes and 2,494 (1.2%) controls died. Amateur athletes had a 30% lower risk of death (hazard ratio 0.70; 95% CI 0.67-0.74, Figure 1) compared to controls, after adjustment for age and sex. Conclusion Participants of a mass-participation exercise event had a non-significant increased odds of death within 8-days after the event. In contrast, mortality risk was significantly lower for amateur athletes compared to controls from the general population during long-term follow-up, emphasizing that the health benefits of exercise and participation in a mass-participation exercise event outweigh the risks. Figure 1. Stratified Kaplan-Meier curves with hazard ratio (HR) adjusted for age and sex for amateur athletes compared to controls.