[Prevalence study on dementia and Alzheimer disease].

An epidemiological survey on dementia and Alzheimer disease (AD) was carried out in a community of 5055 persons over the age of 55 at Jingan district of Shanghai. Diagnoses were made according to the diagnostic criteria of dementia of DSM-III-R and of AD of NINCDS-ADRDA. It was found that dementia is not uncommon in the aged, and AD was the leading category of dementia. The age and sex adjusted prevalence rate of dementia was 2.57% in those over 55, 3.46% in those over 60, and 4.61% in those over 65, and that of AD was 1.50%, 2.05% and 2.90% respectively. Beside age, the other risk factors were female sex, bereavement of spouse, low education and unfavorable socio-economic status.