It's interesting to look at the list of factors from the article - there's an obvious set of physical factors (obesity, cholesterol, smoking, etc), and then the

It's interesting to look at the list of factors from the article - there's an obvious set of physical factors (obesity, cholesterol, smoking, etc), and then there's things like hearing loss, social isolation, and now visual loss, that all seem to be associated with less input to the brain or less informational processing. There's also the studies around staying cognitively active - my understanding is a lot of that is building additional capacity so the effects of dementia & Alzheimers are less noticeable, but it's interesting to see this kind of almost "hardware/software" split in the risk factors. Depression is an interesting one because it's so multicausal that I'd almost wonder if it's a comorbidity, rather than a risk factor.