dementia on the decline

A new study finds that the prevalence of dementia has fallen sharply in recent years, most likely as a result of Americans' rising educational levels and better heart health, which are both closely related to brain health.

Dementia rates in people over age 65 fell from 11.6 percent in 2000 to 8.8 percent in 2012, a decline of 24 percent, according to a study of more than 21,000 people across the country published Monday in JAMA Internal Medicine.

"It's definitely good news," said Dr. Kenneth Langa, a professor of internal medicine at the University of Michigan and a coauthor of the new study. "Even without a cure for Alzheimer's disease or a new medication, there are things that we can do socially and medically and behaviorally that can significantly reduce the risk."

While advocates for people with dementia welcomed the news, they noted that Alzheimer's disease and other forms of memory loss remain a serious burden for the nation and the world. Up to five million Americans today suffer from dementia, a number that is expected to triple by 2050, as people live longer and the elderly population increases.

Although researchers can't definitively explain why dementia rates are decreasing, Langa said doctors may be doing a better job controlling high blood pressure and diabetes, which can both boost the risk of age-related memory problems. High blood pressure and diabetes both increase the risk of strokes, which kill brain cells, increasing the risk of vascular dementia.

"We've been saying now for several years that what's good for your heart is good for your head," Fargo said. "There are several things you can do to reduce your risk for dementia."

Authors of the study found that senior citizens today are better educated than even half a generation ago. The population studied in 2012 stayed in school 13 years, while the seniors studied in 2000 had about 12 years of education, according to the study.

That's significant, because many studies have found a strong link between higher educational levels and lower risk of disease, including dementia, Lang said. The reasons are likely to be complex. People with more education tend to earn more money and have better access to health care. They're less likely to smoke, more likely to exercise and less likely to be overweight. People with more education also may live in safer neighborhoods and have less stress.

People who are better educated may have more intellectually stimulating jobs and hobbies that help exercise their brains, Lang said.