Considering that Alzheimers itself is considered type 3 diabetes and Dementia is heavily correlated, it isn't that surprising.

My own PoV is that a lot of it comes down to the massive increase in heavily refined foods and seed oils in the past century and a half. You have a lot of carbs and a really different mix of fatty and amino acids. So higher blood glucose, more of the time combined with a very different mix of fatty and even amino acids in the diet. Likely exacerbated by half a century of low-fat, low cholesterol diets perpetuated largely in busted myth. Combine this with hyper-palatability and it's just hard to get away from.

Heart disease, alzheimer's, dementia, diabetes, obesity... All of it comes down to food and exercise. With a bit more exposure from RFKjr, it's ironic that Time magazine is now doubling down for the conglomerates, can't find the cover photo for this, but the recent article on why ultra-processed foods aren't that bad is astounding.