Cognitive function and incidence of stroke in older Mexican Americans

Background. Given the high prevalence of cognitive impairment in older Mexican Americans and limited longitudinal research examining cognitive function in this ethnic group, we conducted a study examining whether cognitive impairment is a risk factor for new onset of stroke among older Mexican Americans. Methods. We performed a prospective cohort study of 2682 Mexican Americans aged 65 years and older living in the southwestem United States. For subjects with no prior history of stroke and who completed the Mini-Mental State Examination (MMSE) at baseline, stroke incidence was assessed after 2, 5, and 7 years of follow-up. Results. In Cox proportional regression models, MMSE score at baseline predicted risk of incident stroke over a 7-year follow-up period. For the unadjusted model, subjects with an MMSE score of 21 or higher were half as likely to report stroke at follow-up (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.35-0.69; p < .001) compared with those with a score of less than 21. We found similar results after controlling for relevant risk factors for stroke including age, gender, smoking status, education, body mass index, diabetes, heart attack, systolic blood pressure, and depressive symptoms (HR, 0.54; 95% CI, 0.38-0.77; p = .001). Additionally, each 1-point increase in MMSE score was associated with a 5% reduction in risk (HR, 0.95; 95% CI, 0.92-0.99; p = .01). Conclusions. Increasing MMSE score is associated with a decreasing incidence of stroke in older Mexican Americans. This study highlights the need for a more aggressive focus on identifying and addressing cognitive decline in the Mexican American population.