Dementia rates are dropping

According to a new study by the National Institute on Aging, the dementia rate in Americans 65 and older fell by 24 percent over 12 years. In 2000, people received a diagnosis of dementia at an average age of 80.7; in 2012 the average age was 82.4. Nobody knows why.

The study was nationally representative. That is, it included all races, education, and income levels. The study included 21,000 Americans 65 and older who participate in the Health and Retirement Study which regularly surveys people and follows them as they age. To assess dementia, participants are asked, among other things, to recall 10 nouns immediately and after a delay, to serially subtract seven from 100, and to count backward from 20.

Researchers were surprised about these results, especially given the increase in diabetes, which supposedly increases the risk of dementia. The study also reaffirmed another finding: that those with more education were less likely to develop dementia than those with less. But here’s what I love: compared with people of normal weight, overweight and obese people had a 30 percent lower risk of dementia.

Four to five million Americans develop dementia each year. It is the most expensive disease in America, costing up to $215 billion a year, surpassing heart disease at $102 billion and cancer at $77 billion.

I would hate to take the test for dementia. I’m not sure I could easily subtract seven from 100, and on down, or even remember 10 nouns. However, I’m quite certain I can count backward from 20. I’m thinking I might start practicing with the words and subtraction so I can ace the test.

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