Transient ischemic attack associated with increased risk of dementia

by American Academy of Neurology

edited by Sadie Harley, reviewed by Andrew Zinin

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Having a transient ischemic attack (TIA) is associated with an increased risk of developing dementia, according to a new study published in Neurology. The study does not prove that a transient ischemic attack causes dementia; it only shows an association.

A TIA is when blood flow stops to a part of the brain for a short time, causing stroke-like symptoms that go away within a day with no stroke visible on brain scans. It can be a precursor to a full stroke.

"After a transient ischemic attack, there is a well-established increased risk of stroke, but less is known about the risk of dementia," said study author Raed A. Joundi, MD, DPhil, of McMaster University and the Population Health Research Institute in Hamilton, Canada. "In our study, over an average of seven years, one in five people who had a TIA developed dementia."

For the study, researchers looked at two decades of health data in Ontario to identify 113,081 people with an average age of 70 who had a first transient ischemic attack and no prior history of dementia. These participants were matched for age, sex and health factors such as diabetes and blood pressure to people who did not have a stroke or dementia. They were also matched separately to people who had a first stroke.

Participants were followed for an average of seven years. During this time, 19% of people with TIA had a new diagnosis of dementia, compared with 15% of those without stroke or TIA and 20% of those with a stroke.

Among people with TIA, there were 2.71 new cases of dementia per 100 person-years, compared with 2.03 cases per 100 person-years among people without TIA. Person-years represent both the number of people in the study and the amount of time each person spent in the study.

Researchers found the risk of developing dementia was highest in the first year after a TIA. After matching for age, sex, urban or rural residence, vascular risk factors like high blood pressure and diabetes, people with transient ischemic attack had a 75% increased risk of dementia in the first year compared with those without stroke. Researchers said the risk declined but remained elevated over 20 years, with an overall increased risk of 34%.

Compared with people who had a stroke, people who had a transient ischemic attack had a 33% lower risk of dementia in the first year, but after five years, the risk was similar.

People who had a TIA were three times more likely to develop dementia over the entire follow-up period than to have a stroke.

"Transient ischemic attack is associated with a large and sustained increase in dementia risk," said Joundi. "In addition, dementia occurs far more frequently after a TIA than having a stroke. This highlights that prevention strategies after a TIA should go beyond stroke prevention and consider dementia as a major long-term complication."

A limitation of the study was that researchers did not have detailed brain imaging to determine whether people had hidden disease at the start of or during the study.

The analysis for this study was done at ICES, a health research institute in Ontario.

Publication details

Neurology (2026).

Journal information: Neurology

Key medical concepts

Transient Ischemic AttackDementiaStroke

Clinical categories

NeurologyCommon illnesses & Prevention Provided by American Academy of Neurology Who's behind this story?

Sadie Harley

BSc Life Sciences & Ecology. Microbiology lab background with pharmaceutical news experience in oil, gas, and renewable industries. Full profile →

Andrew Zinin

Master's in physics with research experience. Long-time science news enthusiast. Plays key role in Science X's editorial success. Full profile →

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