alt Hacker NewsNearly 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!