This is a linkpost for https://www.eurekalert.org/pub_releases/2016-12/uoef-fsb121616.php
"The more frequently saunas were taken, the lower was the risk of dementia. Among those taking a sauna 4-7 times a week, the risk of any form of dementia was 66% lower and the risk of Alzheimer's disease 65% lower than among those taking a sauna just once a week. "
that seems more effective than any single medical intervention i have seen, even the sonogram and strobe light tech were less efficacious than this.
As a very shitty theory; the results might be able to be explained by frequency of exercise associated with sauna use. i.e. if I go in the sauna every time I gym and I gym 7 days a week instead of 1 day a week I can presume that means I am healthier or am more likely to be healthier.
Previous results from the KIHD study have shown that frequent sauna bathing also significantly reduces the risk of sudden cardiac death, the risk of death due to coronary artery disease and other cardiac events, as well as overall mortality. According to Professor Jari Laukkanen, the study leader, sauna bathing may protect both the heart and memory to some extent via similar, still poorly known mechanisms. “However, it is known that cardiovascular health affects the brain as well. The sense of well-being and relaxation experienced during sauna bathing may also play a role.”
As I would expect with general health. I barely know anyone who uses a sauna, let alone anyone who uses one 7 days a week. Mainly due to them mostly existing in conjunction with health infrastructure like gyms and swimming pools.
Note that the study is from Finland, where sauna-going is not particularly associated with exercise: people just go into the sauna for its own sake. There are saunas in conjunction of gyms, yes, but e.g. apartment buildings often have their own dedicated saunas that the tenants can reserve for their own use. (Somebody having a single one-hour sauna shift per week is typical.)
That said, there are probably other confounders in that e.g. people who can use a sauna seven times a week are a lot more likely to have a sauna of their own, so live in their own house rather than an apartment, among other things.
I wonder what the statistical power of the study was.
With n = ~2000, and dementia rates being relatively low, and there either being no controls or some lame half-missing linear controls (even worse than no control, because it makes you think the control worked), and the treatment being seemingly arbitrary ,I basically am going to assume this is meaningless information.
It's turning an uncontrolled correlation in a low power sample into a causal story of protection.
Anyway, I didn't actually read the paper so maybe I'm being unfair. I somehow doubt that's the case though.
Thinking along basically the same lines, I tried to access the actual paper via its DOI link and got redirected to a "Production in progress" page. So we have what looks suspiciously like an embargo!