In Reply We thank both Kivimäki et al and Epstein and Shoenfeld for their comments about the association of sauna bathing and fatal cardiovascular events. We agree that observational studies cannot establish causality of the relationship given that the potential for residual confounding or reverse causation cannot be totally eliminated, as discussed in our article.1 However, we did observe graded inverse associations with sudden cardiac death (SCD), fatal coronary heart disease (CHD), and cardiovascular disease (CVD) events, which are the characteristics of a true inverse association between sauna bathing and outcomes. Furthermore, results were carefully adjusted for socioeconomic status (SES), physical activity, and cardiorespiratory fitness, all 3 of which are potential surrogate markers of healthy lifestyle.
Laukkanen T, Khan H, Zaccardi F. The Link Between Sauna Bathing and Mortality May Be Noncausal—Reply. JAMA Intern Med. 2015;175(10):1719. doi:10.1001/jamainternmed.2015.3432