The Demography of Dementia

With aging comes dementia. Maybe not to you personally (hopefully!) but at the population level, your chances of dementia increase with age. But how quickly do those odds increase? A new report out in JAMA Internal Medicine offers a bit of good news, if there is such a thing when it comes to dementia. You can read the whole article on your own, but today's NYTimes offers a summary.

Despite fears that dementia rates were going to explode as the population grows older and fatter, and has more diabetesand high blood pressure, a large nationally representative survey has found the reverse. Dementia is actually on the wane. And when people do get dementia, they get it at older and older ages.

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. That trend is “statistically significant and impressive,” said Samuel Preston, a demographer at the University of Pennsylvania [and a Past President of the Population Association of America] who was not associated with the study.

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

Keep in mind that this is a good new/bad news sort of story. The good news is that the rate of dementia is going down and is hitting at later ages. The bad news is that given the size of the baby boomer population coming into the older ages, that rate is going to have to go down a lot more to ward off a huge national increase in the number of older people with dementia. Nature had a lengthy story recently that details some of those numbers and the fact that we have not yet put nearly enough money or effort into preventing and combatting dementia.

Voluntarily or not, people will need to face up to dementia, because in just a few short decades, pretty much everyone is going to have a friend or loved one affected by the disease. It’s an alarming idea, and it should spur action, says Robert Egge, chief public policy officer of the Alzheimer’s Association in Chicago, Illinois.

So, we can't let the good news from today's research keep us from pressing on with more work on dementia.