The study, which included more than 2300 middle-aged men un Finland, showed that frequent sauna users were 66% less likely to develop dementia and 65% less likely to develop Alzheimer´s than occasional users.
The mean follow-up time was 20.7 years. For each group, from the least sauna use to the most, the percentages with a dementia diagnosis were 10%, 9%, and 4%, respectively; 6%, 6%, and 3% had an AD diagnosis.
After adjustment for a multitude of factors, including age, body mass index, smoking status, alcohol consumption, and having had a prior myocardial infarction, the hazard ratio (HR) for dementia was 0.34 for the 4 to 7 times per week sauna bathers vs the once a week bathers (95% confidence interval [CI], 0.16 – 0.71; P = .004).
The HR for AD for the same comparison was 0.35 (95% CI, 0.14 – 0.90; P = .03).
There were no significant associations with dementia or AD for the 2 to 3 times per week vs once per week sauna bathers.
Overall, the findings show «a strong inverse association between frequency of sauna bathing and the risk of dementia and [AD], which was independent of known risk factors,» write the investigators.
They note that recent evidence has suggested that inflammation and oxidative stress may contribute to the pathogenesis of dementia.
«Our results are therefore biologically plausible as regular sauna bathing is associated with improved vascular endothelial function, which also leads to reduced inflammation,» the researchers write.
Dr Laukkanen added that he thinks the results are generalizable «to other populations in the northern part of the world: in northern countries in Europe and in North America, where they have cold weather. But I don’t know how generalizable it would be in warmer countries.»
He reported that the researchers are planning future studies that will assess these associations in women and assess other physiologic changes with sauna use.
The study was funded by the Finnish Foundation for Cardiovascular Research. Dr Laukkanen and the other study authors have disclosed no relevant financial relationships.
Link Original: http://www.medscape.com/viewarticle/873851?src=soc_fb_170102_mscpedt_news_neuro_sauna#vp_2