Ethnic differences in Mini-Mental State Examination (MMSE) scores: Where you live makes a difference

OBJECTIVES: To examine differences in correlates of the Mini-Mental State Examination (MMSE) in a population-based sample of older Mexican Americans and European Americans and to provide empirical validation of the MMSE as an indicator of cognitive impairment in survey research in older Mexican Americans by comparing MMSE classification against performance on timed tasks with varying levels of cognitive demand. DESIGN: A population-based cross-sectional study. SETTING: Trained bilingual staff administered the MMSE as part of the San Antonio Longitudinal Study of Aging (SALSA) home-based assessment battery. PARTICIPANTS: 827 community-dwelling Mexican Americans and European Americans, 65 and older, residing in three socioeconomically and culturally distinct neighborhoods (barrio, transitional, suburban). MEASUREMENTS: The MMSE was compared against a variety of demographic, biomedical, and sociocultural variables ascertained by self-report and against performance-based measures of functional tasks representing varying levels of cognitive demand (Structured Assessment of Independent Living Skills (SAILS) subscales for food manipulation and money management). RESULTS: Mexican Americans were 2.2 times more likely than European Americans to have MMSE scores < 24, Multiple logistic regression analysis revealed that neighborhood was an independent predictor of low MMSE scores in Mexican Americans, with the relationship between ethnic group and MMSE explained by neighborhood. After adjusting for neighborhood type, no differences were noted between Mexican Americans and European Americans. Independent of other factors examined, low education was associated with low MMSE scores in both Mexican Americans and European Americans. Mexican Americans with MMSE scores < 24 took significantly longer to complete four out of: five performance-based food manipulation tasks and all three money management tasks. CONCLUSIONS: Neighborhood typo was a predictor of cognitive impairment. Education affected MMSE scores similarly in both ethnic groups. MMSE scores < 24, indicative of cognitive impairment, were uniformly associated with functional impairment in both the Mexican Americans and European Americans. Among older Mexican Americans, MMSE-classified cognitive impairment was significantly associated with poorer performance on timed tasks with varying levels of cognitive demand independent of ether correlates. A similar pattern of association was observed in European Americans. Thus, the MMSE appears to be a valid indicator of cognitive impairment in survey research in both older Mexican Americans and European Americans.