Stroke survivors have twice the risk of dementia compared to stroke-free men and women of the same age

“The risk of dementia increases dramatically with advancing age.  Our results show that sustaining a stroke increases this risk even further,” said lead author Cristina S. Ivan, M.D. a fellow in stroke and cerebrovascular disorders at the Boston Medical Center.  “Dementia is a growing problem because of the aging of the population, particularly the ‘baby boomers’.”

Data for this research comes from a subset of the original participants in the Framingham Study, the nation’s longest-running investigation of risk factors for heart and blood vessel disease.  The subjects – predominantly white men and women from the Framingham, Mass., area – began undergoing surveillance for stroke in 1950 and for dementia in 1975.  The current study compared 212 men and women who had a stroke between 1982 and 2001 with 1,060 controls who were stroke-free.  None of the people with stroke had dementia prior to the stroke.

“Dementia developed in 19.3 percent of the stroke cases and in 11 percent of the controls.  Having a stroke doubled the risk of dementia. Adjusting for age, sex, education and exposure to individual stroke risk factors such as high blood pressure, diabetes and smoking did not diminish the risk,” Ivan said.

The finding that the harmful impact of a stroke on cognition is strong and independent of the stroke risk factors means that one of the best ways to reduce the incidence of dementia is to help people avoid strokes, she explained.

She added that the 10-year follow-up period and data from a prospective community-based population, rather than hospitalized subjects, make this study unique.

“More than 700,000 strokes occur each year in the United States.  The impact of those strokes on our aging population will certainly place enormous financial and emotional burdens on society and patients’ families.  Our efforts should be toward prevention,” Ivan said.

Co-authors are Sudha Seshadri, M.D.; Alexa Beiser, Ph.D.; Rhoda Au, Ph.D.; Carlos S. Kase, M.D.; Margaret Kelly-Hayes, R.N., Ed.D.; and Philip A. Wolf, M.D. 

The study was funded by the National Institutes of Health; the National Institute of Neurological Disorders and Stroke; the National Institute on Aging; the National Heart, Lung, and Blood Institute; and Boston University Alzheimer’s Disease Center.