Although transient ischemic attacks (TIA) can affect cognition, their association with long-term dementia risk remains poorly characterized. Researchers assessed the rate, relative risk, and time course of incident dementia after TIA using population-wide health data from Ontario, Canada. The analysis included 113,081 matched patients with TIA, with a mean age of 70 years. During a mean follow-up of 7.11 years, 19.3% were diagnosed with dementia.

Compared with matched controls, dementia rates were consistently higher after TIA across all time horizons, with an overall rate of 2.71 versus 2.03 per 100 person-years. The hazard ratio (HR) for dementia was highest during the first year after TIA (HR, 1.75) and remained elevated over 20 years of follow-up (overall HR, 1.34). Compared with stroke, the hazard of dementia was initially lower after TIA (1-year HR, 0.67), but the difference…