Although we ve frequently been warned that our aging population will doom us to an epidemic of dementia in older folks, a new review in the current New England Journal of Medicine provides some hope that this may not be the case.
Dr. Eric B. Larson of the University of Washington in Seattle and colleagues reviewed several cohort studies that indicated a decrease in the prevalence or incidence of dementia including Alzheimer s disease and other types of dementia in the United States as well as in other developed countries.
For example, Larson et al. cited a 2005 study of U.S. long-term care surveys that included data from 1982 through 1999. The results of those surveys indicated a decrease in the prevalence of dementia from 5.7 percent to 2.9 percent in people aged 65 years and older. Similarly, a British study of the prevalence of dementia in 3 regions declined from 8.3 percent in surveys done in 1989-1994 to 6.5 percent in surveys done between 2008 and 2011. Again, study subjects were aged 65 years or older.
In each of these studies and others, the researchers pointed to higher educational levels, reduction in the incidence of stroke as well as better prevention of vascular disease as factors linked to the decreased numbers of people with dementia.
Dr. Larson and his colleagues suggest Knowing about contributing factors is especially important for the study and development of prevention strategies, and prevention is often the key to better control of epidemics, including epidemics of chronic diseases. They also note [T]he consistency of these recent findings is encouraging and noteworthy, especially since the projected growth of the population older than 75 years guarantees a growing epidemic of dementia.
ACSH s Dr. Ruth Kava adds This review of studies lends hope that preventing dementia may indeed be possible through better education and improved control of contributing lifestyle factors such as control of high blood pressure (a risk factor for stroke). We should be increasingly emphasizing to younger people how important it is to avoid practices (such as smoking and overeating) that might have an impact on later cognitive decline.