Research Summary

Risk of Dementia Increases in People the First Year After a Stroke

Jessica Ganga

The risk of developing dementia may increase after an individual has a stroke, according to a news release by the American Heart Association and findings presented at the American Stroke Association’s International Stroke Conference 2024 in Phoenix, Arizona.

To evaluate dementia risk after stroke, the researchers—using a pool of more than 15 million people in the province of Ontario—identified people who had a recent stroke (n = 180,940). Researchers used databases at the Institute for Clinical Evaluative Sciences at the University of Toronto, Canada. The data included people who had experienced either an ischemic stroke or intracerebral hemorrhage. Those who had a stroke were matched with two control groups—people in the general population who had not had a myocardial infarction or stroke and those who had a myocardial infarction and not a stroke.

The rate of new cases of dementia starting at 90 days after stroke over an average follow-up of 5.5 years was evaluated by researchers, and they analyzed the risk of developing dementia in the first year after the stroke to 20 years.

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The researchers made several key findings. First, the risk of dementia was highest in an individual in the first year after experiencing a stroke, with a nearly 3-fold increased risk, which decreased to a 1.5-fold increased risk by the 5-year mark, remaining elevated 20 years later. Second, over an average follow-up of 5.5 years, dementia occurred in nearly 19% of those who experienced a stroke. Third, the risk of dementia was 80% higher in individuals who experienced a stroke than in the matched group from the general population. Further, the risk of dementia was nearly 80% higher in those who experienced a stroke than in the control group of people who had a myocardial infarction. And lastly, the risk of dementia was nearly 150% higher in individuals who had an intracerebral hemorrhage than those in the general population.

“We found that the rate of post-stroke dementia was higher than the rate of recurrent stroke over the same time period,” said lead study author Raed Joundi, MD, DPhil, an assistant professor at McMaster University in Hamilton, Ontario, Canada, and an investigator at the Population Health Research Institute, a joint institute of McMaster University and Hamilton Health Sciences. “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.”



Risk of dementia was nearly three times higher the first year after a stroke. New release. American Heart Association; February 1, 2024. Accessed June 5, 2024.