With all the research into dementia and its causes, if there was a simple strong link to overweight I can't imagine that would not stand out in the data and be well known by now.
Edit: although, there are well-known links between overweight and a lot of negative outcomes, and yet people are still too fat.
Nearly 75% of Americans are overweight. (over 30% 'overweight', over 40% 'obese').
Obviously, 75% of Americans do not develop dementia. Do more who are overweight develop dementia than those who are not? Well...it's hard to say when 3/4ths of the population is overweight.
Actually that makes it really easy to tell. If one side were very rare maybe we’d miss a subtle effect. But at 3:1 we should see plenty!
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