[Prevalence of dementia in Shanghai urban and rural area].
OBJECTIVE
To study the prevalence and epidemiological characteristics of dementia and their major types in people aged 55 years and old in urban and rural area, Shanghai.


METHODS
A sample with 17,018 residents aged 55 years and above from 22 urban and 14 rural communities was drawn through a stratified multiple stage cluster sampling. A door-to-door three-phase procedure was used to investigate the prevalence of dementia. In 1997 and 1998, A brief memory testing by MMSE was administered to all participants. In phase 2, those who scored below the cutoff points and four percent of those whose score was in the normal range were interviewed to identify dementia through a set of diagnostic examinations according to the DSM-IV criteria. In phase 3, a follow-up program was conducted in 1998 for all persons who was involved in phase 2 to identify those with Alzheimer's dementia (AD) and vascular dementia (VaD) by NINCDS-ADRDA and NINDS-AIREN criteria.


RESULTS
Of the targeted sample, 15,910 (94.2%) were interviewed. The overall prevalence of dementia was 3.0% in individuals aged 55 years and above, 4.32% in those aged 65 years old and 5.29% in those aged 70 years and above. The age-adjusted prevalence rates of dementia were 2.03%, 3.78% and 5.48% respectively among the age groups mentioned above. For AD the age-adjusted prevalence rates were 1.37%, 2.71% and 4.13% for individuals in above age groups. Of all types of dementia, AD was accounted 72%, followed by VaD the second. The prevalence of AD was 1.41% in man comparing to 2.78% in woman. The age-specific prevalence of AD increased with age.


CONCLUSIONS
The prevalence of dementia was 3.0% in individuals aged 55 years in urban and rural areas in Shanghai. Alzheimer's disease was more frequent than VaD.
Zhou
B
B
Huashan Hospital Institute of Neurology, Shanghai 200040, China.
Hong
Z
Z
Huang
M
M
D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology*; D002681:China / Q000453:epidemiology; D003704:Dementia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012423:Rural Health / Q000706:statistics & numerical data