Exploring why dementia rates are declining

A decline in the incidence of dementia may be due to improved management of cardiovascular risks, according to Harvard T.H. Chan School of Public Health’s Albert Hofman.

Although sheer numbers of people with dementia are on the rise because of increasing life expectancy, per capita cases are decreasing, according to a recent study co-authored by Hofman, Stephen B. Kay Family Professor of Public Health and Clinical Epidemiology and chair of the Department of Epidemiology. The paper found a 13% decline in the dementia incidence rate in Europe and North America over the past three decades.

Better control of cardiovascular risks such as hypertension, high cholesterol, and smoking may be driving the declining dementia rates, said Hofman in an article in the November-December 2020 issue of Harvard Magazine. While the physiological mechanism relating cardiovascular risk to dementia isn’t clear, it’s possible that hypertension and other cardiovascular complications might damage small blood vessels leading to the brain. Such damage is “a very strong predictor of dementia” because decreased blood flow in the brain can cause the death of neurons, Hofman said.

Hofman said the threat of dementia may provide people with stronger motivation to protect their cardiovascular health. “There are few things that people fear more than dementia and Alzheimer’s disease,” he noted.

Read the Harvard Magazine article: Lessons in Dementia’s Decline?

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Dementia incidence declined every decade for past thirty years (Harvard Chan School release)