Harvard Women's Health Watch

Dementia rate may be on the decline, major cardiovascular study indicates

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The Framingham Heart Study—which has charted the lifestyles and health status of the residents of Framingham, Mass., since 1948—has been tracking the development of dementia among participants since 1975. In a recent analysis, published in the Feb. 11, 2016, issue of The New England Journal of Medicine, researchers calculated the dementia rate among 5,205 people ages 60 or older. The participants had physical exams, including tests for dementia, every five years. The researchers determined that the five-year rate of dementia was 3.6% between 1982 and 1986, 2.8% between 1991 and 1996, 2.2% between 1998 and 2003, and 2.0% between 2009 and 2013. Moreover, the average age when dementia was diagnosed went from 80 to 85 over those three decades.

The declining dementia rate was registered only in high school graduates, but they made up most of the Framingham participants. The rate of cardiovascular disease—including stroke, atrial fibrillation, and heart failure—also fell during the three decades. In that sense, the results give further support to findings that education (which may build up cognitive reserves) protects against dementia, and cardiovascular disease (which restricts blood flow to the brain) may promote it. They provide encouragement that pursuing a healthy, engaged lifestyle may pay off.