Brett Arends’s ROI: This is now the No. 1 preventable cause of Alzheimer’s in America

Here is yet more bleak news about the obesity epidemic: Obesity isn’t just killing millions of people. It’s giving lots of them Alzheimer’s first.

“Obesity is now the top modifiable dementia risk factor in the U.S.,” reports the Journal of the American Medical Association in its latest bulletin. Obesity in midlife is now leading to more cases of dementia than any of the other usual suspects, including depression, smoking, diabetes, high blood pressure, physical inactivity, or low levels of education. About a third of dementia…