Does the Type of Sporting Activity Affect Risk of Sudden Death?

We appreciate the interest that Mansencal and colleagues have taken in our paper.¹ They pose the question that based on variation in the dynamic and static component of the individual sport, could specific activities pose a higher risk of sudden cardiac arrest (SCA)? Due to several reasons, this important question may be quite difficult to address but we are willing to try. Importantly, the relative distribution of different sports associated with SCA is first and foremost a reflection of the frequency of participation in that sport in the population. Therefore, the popularity of the sport will determine the level of participation, and potentially drive the level of association to SCA. There are limited data suggesting that even after taking frequency of participation into account (looking at incidence per million of specific sports participants), some sports, such as cycling, may be associated with a higher risk of SCA.^{2, 3} Another recent report in younger subjects indicated that certain sports, especially basketball, may be associated with higher risk of an SCA event.⁴ From a practical standpoint we propose that a number of strenuous endurance sports can likely be considered roughly equivalent with respect to risk and benefit. These include, but are not limited to, running, soccer (football), cycling, tennis, swimming, cross country skiing, squash, ice and field hockey, basketball and rugby. Another confounding factor especially in the context of the general population is the variable level of risk of the individual participant. Less strenuous sports such as bowling and golf may be less hazardous but the number of high-risk participants may also be greater. The extent to which SCA risk is related to the specifics of the sporting activity versus the characteristics of the participants, is a subject that clearly requires further investigation.

Regarding sports-associated SCA in subjects < 35 years, given the small population burden we are awaiting feasible numbers of cases to perform a more robust analysis in the Oregon SUDS. In the two European prospective studies, carried out in the general population, the incidence of sports SCA in the <35 year age-group was estimated to be 3–4 per million per year (approximately 10-fold lower compared to the middle age group).^{3, 5}