Stroke Survivors Have Significant Risk of Developing Dementia

A recent study published in Neurology found that stroke survivors have a 76% higher risk of developing dementia compared with those without a history of stroke. The analysis, which evaluated health data from older adults living in Ontario, Canada, found that 18.7% of people with stroke developed dementia compared with 12.5% of those without stroke.

Researchers matched 174,817 patients with a history of ischemic or hemorrhagic stroke with an equal number of people without stroke. The participants, who were aged 69 years on average, were also matched for other factors including age, sex, diabetes, high blood pressure, rural residence, and neighborhood deprivation. Although none of the participants had a previous diagnosis of dementia, there was no information about prior cognitive decline.

Results of the analysis demonstrate that 32,621 stroke survivors were diagnosed with dementia after an average of 5.6 years, while only 21,929 people without stroke received a dementia diagnosis. Notably, the risk of developing dementia following a stroke was double that of experiencing a second stroke. The results also showed that the elevated dementia risk persists long term, though it decreases over time.

Dementia risk was

• 2.5 times higher for stroke survivors at 1 year poststroke
• 1.5 times higher at 5 years
• 1.3 times higher at 20 years 

Patients with recurrent stroke were at a 3 times higher risk for dementia.