The prevalence of dementia in older people in an urban population of Korea: The Seoul study

OBJECTIVES: To estimate prevalence of dementia and its subtypes in older people in Seoul, a metropolitan area of Korea, and compare these findings with estimates reported for other populations. DESIGN: The study employed a two-stage design for case identification. Initially, the Mini-Mental State Examination in the Korean version (MMSE-KC) of the Consortium to Establish a Registry for Alzeheimer's Disease (CERAD) assessment packet was administered to all participants. Two hundred seventeen persons sampled from three levels of performance on MMSE-KC underwent the second-stage clinical evaluation based on the Korean Version of the CERAD assessment packet. SETTING: The study was conducted in an urban community setting. PARTICIPANTS: Six hundred forty-three persons aged 65 and over participated in the study. MEASUREMENTS: Dementia was defined using the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnostic features of dementia. RESULTS: Dementia prevalence ranged from 2.6% in persons aged 65 to 69 to 32.6% in persons aged 85 and older. Age-standardized prevalence was 8.2% for dementia, 5.4% for Alzheimer's disease, and 2.0% for vascular dementia. The prevalence estimates, which excluded very mild cases (clinical dementia rating index 0.5), were approximately 5.3% for dementia and 4.3% for Alzheimer's disease. CONCLUSION: The prevalence of dementia in older people in Seoul appears to be somewhat lower than in rural areas of Korea. Considering the difficulties involved in establishing a diagnostic threshold for dementia, actual differences in dementia prevalence between Asian populations are probably minimal.