Prevalence of Alzheimer's disease, vascular dementia and dementia with Lewy bodies in a Japanese population

We studied the prevalence of dementing disorders in a rural town of Japan ( Amino-cho), using a door-to-door two-phase design. Of the 170 persons scree ned as having cognitive impairment, 142 cases were diagnosed as having deme ntia. The prevalence (cases/100 aged 65 years older) was 3.8 for all types of dementia, 2.1 for Alzheimer's disease (AD), 1.0 for vascular dementia (V D) and 0.7 for other types of dementia. Among other types of dementia, ther e were four male patients with dementia with Lewy bodies (prevalence: 0.1), but no patients with frontotemporal lobar degeneration. The overall preval ence was higher in women for AD, while that of VD was the same in both sexe s. With results similar to many previous studies in Western countries and s ome recent surveys in Japan, the present sudy clearly showed that AD is mor e prevalent than VD.