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 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.
Much of what is happening with dementia rates defies explanation, said Dr. Langa, a professor of medicine at the University of Michigan in Ann Arbor, who also works in the Veterans Affairs health care system there.
The decline is consistent with what seems to be a long-term trend, despite researchers’ failure to find any effective way for individuals to protect themselves from Alzheimer’s, the most common form of dementia. Dr. Langa estimates that compared with the rate in the early 1990s, there has been a 25 to 30 percent decrease in dementia rates among older Americans.
This is great news. Dementia in a loved one is no happy thing, and the less of it, the better. I suspect there is some environmental factor we have not yet identified that is responsible for this, but who knows. Smarter people living longer, more productive lives is just an awesome thing.