1.¬†Sauna bathing is inversely associated with dementia and¬†Alzheimer’s disease in middle-aged Finnish men.

Age Ageing. 2017 Mar 1;46(2):245-249. doi: 10.1093/ageing/afw212.

Abstract

Background:¬†there are no previous studies linking repeated heat exposure of¬†sauna¬†and the risk of memory diseases. We aimed to investigate whether frequency of¬†sauna¬†bathing is associated with risk of dementia and¬†Alzheimer‘s¬†disease.

Setting: prospective population-based study.

Methods:The frequency of¬†sauna¬†bathing was assessed at baseline in the Kuopio Ischaemic Heart¬†Disease¬†population-based prospective cohort study of 2,315 apparently healthy men aged 42-60 years at baseline, with baseline examinations conducted between 1984 and 1989. Hazard ratios (HRs) with 95% confidence intervals (CIs) for dementia and¬†Alzheimer‘s¬†disease¬†were ascertained using Cox-regression modelling with adjustment for potential confounders.

Results:¬†During a median follow-up of 20.7 (interquartile range 18.1-22.6) years, a total of 204 and 123 diagnosed cases of dementia and¬†Alzheimer‘s¬†disease¬†were respectively recorded. In analysis adjusted for age, alcohol consumption, body mass index, systolic blood pressure, smoking status, Type 2 diabetes, previous myocardial infarction, resting heart rate and serum low-density lipoprotein cholesterol, compared with men with only 1¬†sauna¬†bathing session per week, the HR for dementia was 0.78 (95% CI: 0.57-1.06) for 2-3¬†sauna¬†bathing sessions per week and 0.34 (95% CI: 0.16-0.71) for 4-7¬†sauna¬†bathing sessions per week. The corresponding HRs for¬†Alzheimer‘s¬†disease¬†were 0.80 (95% CI: 0.53-1.20) and 0.35 (95% CI: 0.14-0.90).

Conclusion:

In this male population, moderate to high frequency of¬†sauna¬†bathing was associated with lowered risks of dementia and¬†Alzheimer‘s¬†disease. Further studies are warranted to establish the potential mechanisms linking¬†sauna¬†bathing and memory diseases.