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

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).

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).

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 (X² 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.

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.