Stroke, Cardiovascular Disease, and Dementia After Hospitalized TIA: The Atherosclerosis Risk in Communities Study

There are inconsistent data on the long-term risk of dementia after TIA. We used the multidecade Atherosclerosis Risk in Communities (ARIC) study to examine long-term risk of incident dementia and other post-TIA outcomes.

The ARIC study recruited participants from 4 US communities-Minneapolis, MN; Jackson, MS; Forsyth County, NC; and Washington County, MD-during the years 1987-1989. Participants have been followed through in-person visits, phone calls, and hospital and death registry surveillance. Our exposure was the first hospitalized TIA event, ascertained between 1987 and 2020. We report on post-TIA incident events ascertained between 1987 and 2020, including adjudicated dementia, stroke, cardiovascular disease (CVD) events, and mortality. We used Cox proportional hazard regression modeling with TIA as a time-dependent exposure to estimate associations with outcome events. Models were adjusted for demographics and vascular risk factors.

The ARIC study enrolled 15,792 participants (27% Black) aged 45-64 years. Our analytic sample included 13,721 participants (mean age 54 years, 55.5% women) who were without history of hospitalized TIAs or the outcomes of interest at baseline. There were 536 hospitalized TIAs over a median of 29 years. Incident dementia risk almost doubled after TIA (hazard ratio [HR] 1.96; 95% CI 1.66-2.31). Participants who had a TIA were at high risk of stroke (8.14; 6.87-9.64) and CVD (1.52; 1.28-1.82) compared with those without a TIA. They were also at an elevated risk of all-cause mortality (HR 1.55; 95% CI 1.39-1.73) and CVD mortality (1.82; 1.48-2.22). A sensitivity analysis restricted to participants with TIAs but without stroke showed an elevated risk of dementia (HR 1.67; 95% CI 1.37-2.03).

We report an increased risk of dementia after TIA in our multidecade cohort. The elevated risk was present after elimination of stroke as an intermediary variable. Consistent with other studies, we found an increased risk of stroke, CVD, and mortality after TIA. The clinical implications of these results are that in addition to vascular risk factor modification, clinicians should consider incorporating cognitive screening into post-TIA follow-up care.