Differential Impact of Stroke on Cognitive Impairment in Mexican Americans and Non-Hispanic White Americans

Background: The association between stroke and dementia is well established. Less is known about this association in underrepresented ethnic groups. In a large ethnically diverse cohort, we examined whether history of stroke was associated with cognitive impairment, and whether this relationship differed by ethnicity (Mexican American [MA] versus non-Hispanic White). Methods: This was a population-based cohort study conducted in Nueces County, TX, a biethnic community with a large and primarily nonimmigrant MA population. Residents aged >= 65 were recruited door-to-door or by telephone between May 2018 and December 2021. The primary exposure was history of stroke, obtained by self-report. Demographic, medical, and educational histories were also obtained. The primary outcome was the Montreal Cognitive Assessment (MoCA), a scale that evaluates multiple domains of cognitive performance. Scores were divided into 3 ordinal categories, roughly corresponding to normal cognition (MoCA 26-30), mild cognitive impairment (MoCA 20-25), or probable dementia (MoCA 0-19). Results: One thousand eight hundred one participants completed MoCA screening (55% female; 50% MA, 44% Non-Hispanic White, 6% other), of whom 12.4% reported history of stroke. Stroke prevalence was similar across ethnicities (X-2 2.1; P=0.34). In a multivariable cumulative logit regression model for the ordinal cognition outcome, a stroke by ethnicity interaction was observed (P=0.01). Models stratified by ethnicity revealed that stroke was associated with cognitive impairment across ethnicities, but had greater impact on cognition in non-Hispanic Whites (cumulative odds ratio=3.81 [95% CI, 2.37-6.12]) than in MAs (cumulative odds ratio=1.58 [95% CI, 1.04-2.41]). Increased age and lower educational attainment were also associated with cognitive impairment, regardless of ethnicity. Conclusions: History of stroke was associated with increased odds of cognitive impairment after controlling for other factors in both MA and Non-Hispanic White participants. The magnitude of the impact of stroke on cognition was less in MA than in Non-Hispanic White participants.