Yeah, nearly impossible to prove a negative - and on top of that, the Suprachiasmatic Nucleus is damaged early-on in Alzheimers, leading to sleep disturbance..

I'm curious as to whether there's been a SNP associated with normal-short sleep need (or whatever you want to call it). That'd let a researcher with epidemiologic data plus genetics use mendelian randomization to, not exactly show a negative, but to show a very low statistical linkage - or even a negative one, which would be particularly interesting.

Agreed that the etiology of Alzheimer's is unsettled. What does seem settled it that it's the end result of a very long process starting in midlife or earlier.

This has been of interest to me as I both have Alzheimer's in my family (I'm not APOE4) - and missed a lot of sleep as a software developer. Vegetarian distance swimmer all though that period, though...