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Dementia Rate Drops


A new study reported in the Journal of the American Medical Association found that the rate of dementia has dropped in the last twelve years:

The new study found that the dementia rate in Americans 65 and older fell by 24 percent over 12 years, to 8.8 percent in 2012 from 11.6 percent in 2000…

In 2000, people received a diagnosis of dementia at an average age of 80.7; in 2012, the average age was 82.4.

And that “is very good news,” said John Haaga, director of the institute’s [National Institute on Aging] division of behavioral and social research. It means, he said, that “roughly a million and a half people aged 65 and older who do not have dementia now would have had it if the rate in 2000 had been in place.”

(New York Times November 21, 2016. [NYT])

Since between 4 and 5 million people in the US develop dementia every year, this is a major problem.  A study funded by the National Institutes of Health concluded that caring for people with dementia cost more (roughly $215 billion) than caring for those with heart disease ($102 bn) and cancer ($77 bn) combined.

The NYT article also described three simple tests for dementia: a test of recall, immediately and after a five to ten minute delay, for a list of ten nouns; subtracting seven from a hundred repeatedly (serial sevens), and counting backwards from twenty.

The fall in dementia rates occurred despite a dramatic increase in diabetes diagnoses, from 9 percent in 1990 to 21 percent in 2012.  Diabetes increases the risk of dementia by 39 percent.

Dr. Langa, a professor of medicine at the University of Michigan in Ann Arbor, said in the NYT article that the decline in dementia rates is difficult to explain.  Dr. Denis Evans, a professor of medicine at Rush University Medical Center in Chicago, was said to claim that the decline in rates could be spurious because of the difficulty in diagnosing dementia, even though the study was performed by experts.  Nonetheless, Dr. Langa estimated that rates of dementia have declined 25 to 30 percent since the 1990’s.

Whether rates of dementia continue to decline is open to question, but there is cause for optimism because rates of heart disease have also declined, and both dementia and heart disease may be reduced by aggressive treatment of high blood pressure and high cholesterol.  Both conditions have been much more effectively treated recently.

If dementia and heart disease continue to decline in future, then old age may not be so debilitating as it has been in the past.  The elderly may be more independent and may enjoy life more, a possibility to be appreciated by those of us who are getting to be over sixty now.

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