At first glance, a study showing a significant, long-term drop in dementia in the U.S. looks like good news. However, the results apply only to vascular dementia, not Alzheimer’s disease, researchers cautioned in the New England Journal of Medicine last week.
Improvements in cardiovascular health and risk factor control have driven the decline in vascular dementia, even as some contributors to heart disease have been on the rise, wrote Sudha Seshadri, MD, of Boston University, and colleagues. They also noted the significant declines in dementia were seen only among those who had at least a high school education.
The study “offers cautious hope” that dementia might be delayed or prevented in certain cases, but additional research is needed that investigates the factors that contribute to this decline, they stated.
The Framingham Heart Study started in 1948, and dementia has been monitored since 1975. The current analysis, which was sponsored by the National institutes of Health, included 5,205 people age 60 and up. There were a total of 371 cases of dementia over the study period, which included four different time periods: The late 1970s to early 1980s, late ‘80s to early ‘90s, late ‘90s to early 2000s, and late 2000s to early 2010s. Compared with the first time period in the study, dementia incidence fell by 22%, 38%, and 44% over the next three time periods, respectively, according to the researchers.
In addition, the average age of onset of dementia has been increasing steadily, from 80 in the earliest period to 85 in the latest, they stated.
During the course of the study, rates of cardiovascular events also fell, suggesting that earlier diagnosis and more effective treatment of stroke and heart disease may have contributed to a lower incidence of dementia, particularly vascular dementia.
Source: MedPage Today, NEJM