Interactive influences of demographics on the Mini-Mental State Examination (MMSE) and the demographics-adjusted norms for MMSE in elderly Koreans

Abstract

Background: The influences of demographics, culture, language, and environmental changes on Mini-Mental State Examination (MMSE) scores are considerable. Methods: Using a sample of 7452 healthy, community-dwelling elderly Koreans, aged 55 to 94 years, who participated in the four ongoing geriatric cohorts in Korea, we investigated demographic influences on MMSE scores and derived normative data for this population. Geropsychiatrists strictly excluded subjects with cognitive disorders according to the protocol of the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet (CERAD-K) Clinical Assessment Battery (CERAD-K-C). Results: Education (standardized beta = 0.463), age (standardized beta = -0.303), and gender (standardized beta = -0.057) had significant effects on MMSE scores (p < 0.001). The score of MMSE increase 0.379 point per 1-year education, decrease 0.188 per 1-year older, and decrease 0.491 in women compared to men. Education explained 30.4% of the scores' total variance, which was much larger than the variances explained by age (8.4%) or gender (0.3%). Accordingly, we present normative data for the MMSE stratified by education (0, 1-3, 4-6, 7-9, 10-12, and >= 13 years), age (60-69, 70-79, and 80-89 years), and gender. Conclusions: We provide contemporary education-, age-, and gender-stratified norms for the MMSE, derived from a large, community-dwelling elderly Korean population sample, which could be useful in evaluating individual MMSE scores.