Abstract T P365: Does Stroke Contribute to Racial Differences in Cognition?

Abstract

Objective: Although dementia prevalence is higher in blacks than whites, it is unknown whether blacks’ elevated risk of dementia is due to racial differences in acute stroke, the impact of stroke on cognitive health, or other factors. We determined whether racial differences in cognitive function are explained by differences in the frequency or impact of incident stroke between blacks and whites, controlling for baseline cognition. Methods: The study population was a prospective cohort of 5,126 white or black adults aged ≥65 years responding to the Health and Retirement Study in 1998 and followed through 2006. Cognitive function was assessed at 2-year intervals with a modified version of the Telephone Interview for Cognitive Status (TICS-m). Acute strokes were identified using linked Medicare claims. Adults with cognitive impairment (TICS-m<7) in 1998 were excluded. We examined changes in cognitive function over time by race, before and after adjusting for time-dependent acute stroke using linear mixed effects models that also included baseline values of age, sex, education, self-reported history of stroke, depressive symptoms, TICS-m, and random effects for intercept and slope. We then added a race-by-stroke interaction in the model. Results: There were 5,126 adults with ≥1 follow-up TICS-m measure, of whom 490 had acute stroke (466 whites and 24 blacks; P=0.39). Blacks had lower adjusted TICS-m scores than whites (mean difference, -1.41 points; 95% CI, -1.67 to -1.16 points; P<0.001), and this racial difference persisted after adjusting for acute stroke (Table). Acute stroke was associated with average acute decreases in TICS-m scores of about 1.17 points. The association of acute stroke with change in cognition did not differ by race (P for race-by-stroke interaction=0.62). Conclusions: In this nationally representative cohort of older adults, acute stroke did not explain black-white differences in cognition or impact cognition differently by race.