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

Little information is available on the prevalence of cognitive impairment in Mexican American persons.

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.

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.

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)].

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.