Risk of Dementia Is Almost Three Times Higher in the First Year After a Stroke

Individuals who suffer a stroke have a significantly increased risk of developing dementia, according to preliminary research being presented at the American Stroke Association’s International Stroke Conference 2024, taking place February 7-9 in Phoenix, Arizona.

Researchers used databases from the Institute for Clinical Evaluative Sciences at the University of Toronto to analyze 180,940 people who had suffered a recent stroke—either an ischemic stroke or an intracerebral hemorrhage—and matched the stroke survivors to 2 control groups, people in the general population or those who had had a heart attack and not a stroke.

Researchers evaluated the rate of new cases of dementia starting at 90 days after stroke over an average follow-up of 5.5 years. They also analyzed the risk of developing dementia in the first year after the stroke and over time, up to 20 years.

According to the results, the risk of dementia was highest in the first year following stroke, with a nearly 3-fold increased risk. The researchers noted that this risk decreased to a 1.5-fold by the 5-year mark but remained elevated 20 years later. They observed that dementia occurred in nearly 19% of stroke survivors over the average follow-up period. Overall, the risk of dementia was 80% higher in stroke survivors than in the matched group from the general population.

“Our findings show that stroke survivors are uniquely susceptible to dementia, and the risk can be up to 3-times higher in the first year after a stroke. While the risk decreases over time, it remains elevated over the long term,” said lead study author Raed Joundi, MD, DPhil, an assistant professor at McMaster University in Canada and an investigator at the Population Health Research Institute, a joint institute of McMaster University and Hamilton Health Sciences, via a press release.

“We found that the rate of poststroke dementia was higher than the rate of recurrent stroke over the same time period,” Dr. Joundi said. “Stroke injures the brain, including areas critical for cognitive function, which can impact day-to-day functioning. Some people go on to have a recurrent stroke, which increases the risk of dementia even further, and others may experience a progressive cognitive decline similar to a neurodegenerative condition.”