Study: Are Dementia Rates Dropping?

BU research suggests it may be possible to prevent or delay some types of dementia.


Dementia photo via Shutterstock

A new study from Boston University School of Medicine (BUSM) says incidence of dementia may actually be declining.

Many widely disseminated estimates have shown rates of Alzheimers and other dementias climbing, often to a startling degree. The Alzheimer’s Association, for one, projected that the number of Americans living with the disease could balloon to 13.8 million by 2050. BUSM’s research, however, actually shows dementia rates dropping.

So are years of frightening dementia projections just plain wrong?

Not exactly. As estimates have shown, the raw number of people with dementia is growing, simply because more Baby Boomers are reaching old age. The percentage of elderly and late-middle age people developing dementia, however, is on the decline—a phenomenon that the BUSM researchers say is encouraging.

“Other studies have reported on the prevalence, because there will be a lot of people that will age in the next decade, and also we are living longer lives,” explains lead author Claudia Satizabal, an instructor at BUSM. “However, the incidence, which is the new cases we are seeing, is decreasing. This means that we have been doing something to prevent or delay the onset of the disease.”

BUSM researchers examined data from the Framingham Heart Study, a large, long-term study that has monitored its participants for signs of dementia and cognitive decline since 1975. The researchers measured incidences of dementia in the late 70s, 80s, 90s, and 2000s, and saw a roughly 20 percent decline in new instances of dementia each decade. Though it’s not yet possible to pinpoint the precise catalyst for the drop, Satizabal says improved education, physical activity, and diet could all play a role.

Prevalence of dementia linked to conditions like stroke and heart disease saw an especially large drop, a promising finding that suggests better treatment, diagnosis, and prevention of those conditions could also lower dementia rates.

“It’s important to understand that improved cardiovascular health often will translate into better brain aging,” Satizabal says. “That is something that you can actually do to try to diminish your risk of dementia, or try to delay the onset of the disease.”