Don’t misread this new report: the number of people expected to develop all types of dementia is still expected to skyrocket in the coming years, with estimates of more than 13 million older adults in the U.S. afflicted with Alzheimer’s disease by 2050.
But the report offers what researchers call “cautious hope.”
The analysis, based on data from the Framingham Heart Study (FHS), and published in The New England Journal of Medicine, suggests that the rate of new cases of dementia may be declining. Over a period from the late 1970s until the early 2000s, researchers report about a 20 percent reduction in dementia cases per decade. One potential reason: What’s good for your heart is also good for your brain. And the report finds that among the Framingham study participants, at least, overall heart health has generally improved over the decades. (Though obesity and diabetes prevalences have not.)
Claudia Satizabal, the study’s lead author and an instructor of neurology at the Boston University School of Medicine, said in an interview that “with this study, what we’re showing is that we could potentially prevent some cases or delay the onset of [dementia] with improved cardiovascular health.” But, she warned, while the study points to improved heart health as a potential factor in the improved dementia outlook, “we need more research to identify which other factors have contributed to this decline so that we can extend this beneficial trend.”
Researchers began tracking cognitive decline and dementia in the FHS participants beginning in 1975 and into the present; for the current study they rely on data from about 5,000 participants. This analysis involved dividing the years into four time periods — the late ’70s, late ’80s, ‘1990s and 2000s. The researchers estimated the incidence of dementia at any given age in each of those periods for five years.
“We found that there has been a progressive decline in the incidence of all dementias,” Satizabal said. “If we compare to the late ’70s, we observe a decline of 22 percent in the late ’80s, then a 38 percent decline in the 1990s and a 44 percent decline in the 2000s.”
Notably, she said, the decline was more pronounced with a type of dementia caused by strokes. And also notably, the decline was only seen among participants with a high school diploma or above. Higher education, Satizabal said, can often be related to a better quality of life, and better vascular health overall.