Re intermittent fasting - "not clinically relevant" in that its effect on insulin in itself isn't relevant, or that insulin resistance itself doesn't have a clinically significant relationship to dementia?

I'm not a faster, don't have a dog in this fight, just curious as have seen a few papers & articles in recent years that seem to suggest a relationship between T2D / metabolic syndrome and dementia, but these may have since been debunked?