No Link Found Between Transient Ischemic Attack and Long-Term Dementia Risk: Study

A new study published in the Journal of American Heart Association showed no significant difference in dementia incidence between individuals with and without transient ischemic attacks (TIAs), challenging earlier assumptions about TIAs increasing dementia risk.

Stroke accelerates the aging process of the brain by an estimated 25 years. Information on the impact of TIAs is less apparent, despite the fact that the involvement of severe strokes is well documented. TIA and cognitive decline are connected by a number of hypothesized processes. For example, people who have TIA are more likely to have cardiovascular risk factors, which are associated with a higher burden of subclinical cerebral small artery disease, a primary cause of dementia.

Despite having solid theoretical underpinnings, observations from the real world paint a mixed picture. According to some study, executive dysfunction can last up to nine months during the acute TIA phase, whereas population-based studies indicate that TIA speeds up the onset of dementia by around two years. Therefore, this study investigated whether TIA causes changes in vascular risk variables and the long-term incidence of post-TIA dementia.

The community-based Framingham Heart Study includes a nested matched longitudinal cohort study. The participants with a first episode TIA >60 years were matched on age and sex (5:1) with a prospectively gathered sample of individuals without dementia or transient ischemic attack. The 20-year incidence of dementia from all causes was the main outcome of interest.

The study paired 1,485 controls without TIA with 297 TIA individuals, 141 (47%) men, with a mean age of 72.7±7.7 years. Atrial fibrillation, coronary heart disease, and hypertension were all more common in those who had TIA.

353 (24%) controls without TIA and 57 (19%) individuals with TIA had dementia throughout a median follow-up period of 8.9 years (hazard ratio [HR], 0.93 [95% CI, 0.71–1.24], P=0.63). This connection remained unchanged when stroke and the competing risk of mortality were taken into consideration.

There was a slight rise in aspirin usage (46% to 61%, P=0.052), a decrease in smoking frequency (18% to 11%, P=0.025), and an increase in anticoagulant use from 3% to 18% (P=0.0005) among participants with TIA. Overall, there was no discernible difference in the incidence of dementia after a 20-year follow-up period when compared to matched TIA-free controls. These results imply that TIA causes behavioral and therapeutic modifications that reduce cardiovascular risk.

Reference:

Lioutas, V.-A., Peloso, G., Romero, J. R., Aparicio, H., Gonzales, M., Werry, A., Himali, D., Himali, J., Banerjee, A., Gosh, S., Ramachandran, V. S., Beiser, A., & Seshadri, S. (2025). Long-term incidence of dementia following transient ischemic attack: A longitudinal cohort study. Journal of the American Heart Association, e037817. https://doi.org/10.1161/JAHA.124.037817