A Community-Based Study of Dementia in Mexican American and Non-Hispanic White Individuals.

Background: Little information is available on the prevalence of cognitive impairment in Mexican American persons.
Objective: To determine the prevalence of mild cognitive impairment (MCI) and dementia in those 65 years and older among Mexican American and non-Hispanic white individuals in a community.
Methods: This was a population-based cohort study in Nueces County, Texas, USA. Participants were recruited using a random housing sample. The Harmonized Cognitive Assessment (HCAP) participant and informant protocol was performed after Montreal Cognitive Assessment (MoCA) screening. An algorithm was used to sort participants into diagnostic categories: no cognitive impairment, MCI, or dementia. Logistic regression determined the association of ethnicity with MCI and dementia controlling for age, gender, and education.
Results: 1,901 participants completed the MoCA and 547 the HCAP. Mexican Americans were younger and had less educational attainment than non-Hispanic whites. Overall, dementia prevalence was 11.6% (95% CI 9.2-14.0) and MCI prevalence was 21.2% (95% CI 17.5-24.8). After adjusting for age, gender, and education level, there was no significant ethnic difference in the odds of dementia or MCI. Those with ≤11 compared with ≥16 years of education had much higher dementia [OR = 4.9 (95% CI 2.2-11.1)] and MCI risk [OR = 3.5 (95% CI 1.6-7.5)].
Conclusions: Dementia and MCI prevalence were high in both Mexican American and non-Hispanic white populations. Mexican American persons had double the odds of mild cognitive impairment and this was attenuated when age and educational attainment were considered. Educational attainment was a potent predictor of cognitive impairment.