Prevalence of Dementia in the Rural Island Town of Ama-cho, Japan

Background: With the striking increase in the number of elderly people in Japan, dementia has not only become a medical but also a social issue. Methods: We studied the prevalence of dementing disorders in a rural island town of Japan (Ama-cho), using a door-to-door 2-phase design. Results: Of the 120 persons screened as having cognitive impairment, 104 people were diagnosed as having dementia. The prevalence (cases/100 persons aged 65 years and older) was 11.0 for all types of dementia, 7.0 for Alzheimer's disease, 1.7 for vascular dementia, 0.53 for dementia with Lewy bodies, 0.74 for Parkinson's disease dementia, 0.21 for progressive supranuclear palsy, 0.11 for frontotemporal lobar degeneration and 0.74 for other dementia. The overall prevalence was higher in women for Alzheimer's disease and Parkinson's disease dementia, and in men, for vascular dementia and dementia with Lewy bodies. Conclusion: We confirmed the overall prevalence of dementia in the elderly population aged 65 years and older to be 11.0. This finding is higher compared with previous reports in Japan. Copyright (C) 2008 S. Karger AG, Basel