Healthy Bodies Kept Minds Healthy

Dementia incidence may be declining in older individuals

(RxWiki News) As many Americans age, we’ve been told to expect a huge swelling in the rates of dementia, including Alzheimer’s disease. A new review of recent studies shows some improvement being made on this front.

Researchers of five studies discovered that the incidence and prevalence of dementia appeared to be declining among people born later in the 20th Century.

These researchers credited the trends to improved education and healthier lifestyles that have reduced cardiovascular disease and stroke risks.

Study reviewers suggested that finding more effective ways to prevent obesity and diabetes will be key to maintaining these trends.

"Make healthy choices now to improve your health in later years."

Eric B. Larson, MD, MPH, executive director of Group Health Research Institute and Group Health's vice president for research, and colleagues examined five studies which looked at cognitive impairment and dementia in older people.

"Of course, people are tending to live longer, with worldwide populations aging, so there are many new cases of dementia," Dr. Larson said in a statement. "But some seem to be developing it at later ages — and we're optimistic about this lengthening of the time that people can live without dementia."

A study published in 2005 that analyzed long-term care surveys in the US over a 17-year period (1982-1999) found dementia prevalence among people 65 and older decreasing from 5.7 percent to 2.9 percent. The authors of this 2005 study credited this trend to a reduction in strokes and higher education levels.

The US Health and Retirement Study, an ongoing health study of individuals 51 years and older, saw a decline in cognitive impairment among people aged 70 and older. In 1993, 12.2 percent of this age group showed signs of cognitive impairment, compared to 8.7 percent in 2002.

Three European studies found similar trends in dementia and cognitive impairment among older individuals. The researchers in these studies concluded that healthier lifestyles that reduced vascular risk factors (smoking, diabetes, obesity) and reductions in stroke incidence were at the heart of these improvements.

The authors reviewing these studies said the research "… illustrate[s] the potential for deriving widespread public health benefits from such lifestyle interventions as improving educational opportunities in both early and later life, reducing vascular risk factors, and promoting greater physical activity.”

These authors wrote, “Knowing about contributing factors is especially important for the study and development of preventions strategies, and prevention is often the key to better control of epidemics, including epidemics of chronic diseases."

Kenneth M. Langa, MD, PhD, a professor of medicine at the University of Michigan and VA Healthcare System and co-author of this review, said, "We're very encouraged to see a growing number of studies from around the world that suggest that the risk of dementia may be falling due to rising levels of education and better prevention and treatment of key cardiovascular risk factors such as high blood pressure and cholesterol."

There are some dark spots on this brightening horizon, according to the researchers. Increasing prevalence of obesity and diabetes seen in middle-aged and younger individuals could compromise these positive trends.

Dr. Larson said the key to avoiding dementia is finding better and more effective ways to prevent obesity and its attendant health risks, including diabetes and heart disease.

"As luck would have it, preventing obesity and diabetes jibes with preventing dementia," Dr. Larson said. "In other words, we must focus on exercise, diet, education, treating hypertension, and quitting smoking."

This perspective article was published November 27 in the New England Journal of Medicine.

No conflicts of interest were reported.

Review Date: 
November 27, 2013