Stroke survivors face a higher risk of dementia, study finds

A new study reveals that people who survive a stroke are significantly more likely to develop dementia compared to those who have never had a stroke.

Published in the journal Neurology, the research found that stroke survivors have an 80% higher risk of dementia, emphasizing the need for more focus on preventing cognitive decline after a stroke.

The study tracked nearly 175,000 stroke survivors in Ontario, Canada, and compared them to an equal number of people without a history of stroke. Participants, with an average age of 69, were monitored over six years.

Researchers discovered that about 19% of stroke survivors developed dementia during the follow-up period, compared to 13% of those who hadn’t experienced a stroke.

Stroke survivors experienced approximately 3.3 cases of dementia per 100 person-years, while the rate was 1.9 cases among those without a stroke. “Person-years” refers to the total number of people studied multiplied by the amount of time each person was observed.

Importantly, the study found that the risk of dementia after a stroke was twice as high as the risk of experiencing a second stroke. This finding, highlighted by lead researcher Dr. Raed Joundi of McMaster University in Canada, underscores the need to shift some research efforts toward preventing dementia in stroke survivors.

“While much research has focused on reducing the risk of a second stroke, our findings show that preventing dementia after stroke is equally important,” Joundi said in a news release.

The Immediate and Long-Term Risks

The study revealed that the risk of developing dementia was highest immediately after a stroke. Within the first year, stroke survivors were 2.5 times more likely to develop dementia compared to those without a stroke.

Five years after the stroke, the risk dropped to a 50% increase, and at 20 years, the risk was still elevated by 30%.

The researchers accounted for various risk factors like age, gender, high blood pressure, and diabetes, but the increased risk of dementia persisted. These findings highlight the lasting impact a stroke can have on brain health, even decades later.

The Link Between Stroke and Dementia

Strokes occur when blood flow to the brain is either blocked (ischemic stroke) or caused by bleeding (hemorrhagic stroke). Both types of stroke can damage brain tissue, which may contribute to cognitive decline.

While the exact mechanisms linking strokes to dementia are still being studied, the brain injury caused by a stroke likely disrupts networks responsible for memory, thinking, and other cognitive functions.

Understanding these links is crucial, especially as rates of both stroke survival and dementia continue to rise globally. “As more people are surviving strokes and dementia cases increase worldwide, it’s essential to understand how stroke contributes to the risk of dementia,” Joundi said.

Implications for Prevention and Care

This study highlights an urgent need for new strategies to protect stroke survivors from cognitive decline. While efforts to prevent recurrent strokes remain important, more research is needed to identify interventions that can reduce the risk of dementia after a stroke.

This could include therapies aimed at improving brain health, managing risk factors like high blood pressure and diabetes, and providing better support for stroke survivors during recovery.

With dementia rates rising globally, addressing this issue has become a pressing public health concern. Understanding the long-term risks faced by stroke survivors could lead to more effective treatments and improved quality of life for those affected.

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The research findings can be found in Neurology.