Author response: Sauna bathing reduces the risk of stroke in Finnish men and women: A prospective cohort study

We thank Yu et al. for their comment on our article discussing the correlation between sauna bathing and reduction of stroke risk.¹ Yu et al. infer that participants in our study were very likely to have major cervical or intracranial vessel stenosis based on average age. This assertion was based on 2 studies that reported the prevalence of asymptomatic carotid and intracranial stenosis in the general population to range from 0% to 5.7%.^2,3 The figures were higher for men aged 80 years and above, and in Asian, Hispanic, and African American populations. It is unlikely these findings are applicable to our population, which comprised apparently healthy Caucasians aged 53–74 years without a known history of stroke at baseline. Furthermore, of the 197 men who took very frequent baths, only 8 had a stroke. Indeed, we agree that intracranial vasculature status is an important factor to take into account; however, we had no such imaging data available. As with epidemiologic observational studies, there is always a possibility of residual confounding. This bias was minimized by taking into account a comprehensive panel of confounders and conducting several sensitivity analyses. Our results are robust and consistent with previous research data⁴ and the compelling body of evidence on the beneficial physiologic changes associated with sauna bathing.⁵