Dementia among elderly in Shanghai suburb: a rural community survey.

The number of elderly in the world is increasing rapidly, especially in China. The prevalence of dementia among elderly was investigated in a community of Sheshan town, located in the Southwest suburb of Shanghai, China. Face-to-face interviews were conducted to collect relevant information with prepared questionnaires. The Chinese version of the Mini-Mental Status Examination was used to screen subjects with cognitive impairment (CI). Physical examinations and neuropsychological assessments were carried out. Dementia and its major subtypes, Alzheimer's disease (AD) and vascular dementia (VaD), were diagnosed by senior neurologists according to relevant diagnostic criteria. In addition, magnetic resonance imaging and EEG (with P300) were performed for a number of cases with AD or VaD. There were 1,472 participants (666 males and 806 females) aged 60 years and over in the study. A total of 167 subjects with CI were screened. Among them, dementia was recognized in 79 cases with a prevalence of 5.37% (95% confidence intervals: 4.22%-6.52%). The diagnosis of AD was made for 53 cases (16 males and 37 females) with a prevalence of 3.60% (95% confidence intervals: 2.65%-4.55%), and VaD for 21 cases (5 males and 16 females) with a prevalence of 1.43% (95% confidence intervals: 0.82%-2.03%); while the ratio of AD to VaD was 2.52. The prevalence rates of dementia among elderly from our study are higher than that previously reported from China, but in line with that reported from most world regions. A nationwide survey and surveillance system on the prevalence of dementia is recommended.