well, so do 90% of the people in countries with poor sanitation have dementia? I don't think so. It's like saying that smoking weed leads to using hard drugs bec. 90% (or whatever) of the people who use cocaine used weed. They also drank milk as kids. So is milk a gateway drug? of course not.
My husband has had two courses of vancomycin, heavy-duty antibiotic since he's had dementia symptoms.