Abstract DP084: Pre-Stroke Cognitive Impairment is Associated with an Elevated Risk of Incident Stroke: The ARIC-Neurocognitive Study (ARIC-NCS)

Background: Stroke is a leading cause of death and disability despite advances in risk factor management. Many risk factors for stroke have also been implicated as risk factors for mild cognitive impairment (MCI) and dementia. Given these shared risk factors, cognitive impairment (CI) may represent an accumulation of neurological injury that is associated with an elevated risk of stroke. In ARIC-NCS, we aimed to 1) understand the independent relationship between pre-stroke CI (MCI or Dementia) and incident stroke; 2) explore mortality differences in stroke patients with vs without pre-stroke CI; and 3) evaluate modifiers of these relationships. Methods: 5434 stroke-free participants were evaluated for cognitive status at an in-person visit in 2011-13 (visit 5; ages 66-90), based on cognitive testing and informant interviews. Incident definite or probable strokes (ischemic or hemorrhagic) from visit 5 through 2022 were identified via ongoing surveillance (semi-annual telephone calls, with expert classification). Using Cox proportional hazards regression models adjusted for demographics and vascular risk factors, we evaluated associations between CI (MCI or dementia) and incident stroke, and between CI and death among individuals with stroke. Finally, we tested effect modification by age at visit 5, sex, education, and race, via stratified models and formal interaction terms. Results: Compared to those without CI, individuals with CI (23%) were older (77 vs 75 years, p<0.001), and more frequently male (48% vs 40%). Over 10+ years, CI was independently associated with an increased risk of incident stroke (HR:1.52, 95% CI:1.18-1.96). Among individuals with stroke, risk of death was also higher in CI vs non-CI patients (HR 1.78, 95% CI 1.27-2.50). In stratified analysis, we found a significant interaction by sex (p-interaction=0.04): in males, CI was associated with elevated stroke risk (HR:2.01, 95% CI:1.39-2.91) without a similar risk in females (HR:1.22, 95% CI:0.85-1.75). Interactions by race, age, and educational level were not statistically significant, but effect sizes were qualitatively larger in White participants and individuals with more education. Conclusion: CI is associated with incident stroke independent of shared risk factors, especially in men. This work adds to our understanding of populations at risk for stroke, thus aiding efforts to optimize stroke prevention in at-risk populations.