Dementia on the decline for some seniors

Recent studies have found dementia rates have dropped by as much as 25 percent over the past two decades, offering a glimmer of hope after years of bad news about the rapid rise in the number of dementia patients, and the social and economic implications of caring for them.

The reason for the decline, according to researchers? People are healthier and better educated.

The new studies assessed dementia, which includes Alzheimer’s disease but also other conditions that can make mental functioning deteriorate. Dr. Carol Brayne of the Cambridge Institute of Public Health, led a study of more than 7,600 people 65 and older and found rates of dementia fell 25 percent over the past 20 years, to 6.2 percent from 8.3 percent.

Another recent study of more than 3,500 Danish subjects found that people in their 90s who were given a standard test of mental ability in 2010 outperformed those who had reached their 90s a decade before. About 25 percent of those tested in 2010 scored at the highest level, a rate twice that of those tested in 1998.

Dallas Anderson, an expert on the epidemiology of dementia at the National Institute on Aging, told the New York Times that the new studies were “rigorous and are strong evidence” that dementia rates are falling. He added that he expected that the trend is the same in the United States, but that more study was needed.

Because dementia is sometimes caused by mini-strokes and other vascular conditions, it stands to reason that people who control their blood pressure, cholesterol and other cardiovascular risk factors are less likely to develop the condition, said Dr. Jennifer DeBruler, an internal medicine with Advocate Medical Group.

There is also evidence to suggest that the incidence of dementia is lower among those with more education, she said. Researchers think this could be because education typically leads to greater socioeconomic status, but Dr. Brayne contends that a separate 2010 study showed those with more education were better able to compensate for the changes in the brain associated with dementia.

People shouldn’t wait for those results to start taking care of their health, DeBruler said. It’s been well proven that those who are physically and mentally active throughout their lives enter their golden years in a healthier place. And everyone should monitor and manage their cardiovascular health, she added.

“We should see more people reaching old age in better overall health. That includes better cognitive health, which means postponing or preventing dementia,” DeBruler said.