Parkinson's disease in China: prevalence in Beijing, Xian, and Shanghai.

A cross-sectional prevalence study of Parkinson's disease in China was undertaken in 1997-98. We assessed 29?454 residents aged > or =55 years from 79 rural and 58 urban communities in Beijing, Xian, and Shanghai, who were selected through stratified, multistage, cluster sampling. With a standardised diagnostic protocol, we identified 277 people with the disease. Prevalence of Parkinson's disease for those aged > or =65 years was 1.7% (95% CI 1.5-1.9). We estimate that 1.7 million people in China have the disease (aged > or =55 years). Our findings suggest that prevalence of Parkinson's disease in China is similar to that in developed countries.

Dementia subtypes in China: prevalence in Beijing, Xian, Shanghai, and Chengdu.

BACKGROUND: Prevalences of Alzheimer disease (AD) and vascular dementia (VaD) in China reportedly differ from those in Western countries. OBJECTIVE: To estimate prevalence of AD and VaD in 4 regions of China. DESIGN: Cross-sectional, population-based prevalence survey with a stratified, multistage cluster sampling design. SETTING: Rural (n = 99) and urbanized (n = 71) communities of Beijing, Xian, Shanghai, and Chengdu. PARTICIPANTS: A sample of 34 807 community residents (94% of those eligible) 55 years or older. MAIN OUTCOME MEASURES: Participants were screened with the Chinese Mini-Mental State Examination. Those who screened positive (n = 3950) underwent a standardized diagnostic workup. Screening sensitivity was assessed in a 3.3% random sample (n = 1008 of the 30 857 who passed the screening). Diagnoses of AD and VaD were made according to National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer Disease and Related Disorders Association and National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences criteria, respectively. Final diagnoses were made after a 6-month confirmation interval. RESULTS: We identified 732 AD cases and 295 VaD cases. Prevalence in persons 65 years or older was 3.5% (95% confidence interval, 3.0%-3.9%) for AD and 1.1% (95% confidence interval, 0.9%-1.1%) for VaD. After post hoc correction for negative screening errors, prevalence increased to 4.8% for AD and remained at 1.1% for VaD. CONCLUSION: Prevalence of dementia subtypes in China is comparable with that in Western countries.

Socio-demographic variation of dementia subtypes in china: Methodology and results of a prevalence study in Beijing, Chengdu, Shanghai, and Xian.

OBJECTIVE: To characterize sociodemographic variations in the prevalence of AD and VaD in China. METHODS: Data were collected in a 1997-1998, cross-sectional, door-to-door prevalence survey of 34,807 community residents ages > or =55 years in Beijing, Shanghai, Chengdu and Xian. Initial diagnoses of AD and VaD were assessed by clinicians using standardized protocols, according to the NINCDS-ADRDA and NINDS-AIREN criteria; diagnoses were confirmed after 6 months by repeating neuropsychological evaluations. Prevalence odds ratios were estimated in logistic models adjusting for survey design, age, and other sociodemographic factors. RESULTS: We identified 732 prevalent cases of AD and 295 cases of VaD. Adjusting for all sociodemographic factors concurrently, prevalence odds of AD and VaD were higher in northern versus southern China. Age trends for AD appeared different in western and eastern China. AD also showed an age-adjusted elevation among women and, in the fully adjusted model, a gender education interaction indicating a female preponderance in the highest education group. North-south variation for VaD was age-dependent. In the fully adjusted model, for AD, widowed had significantly higher prevalence odds; for VaD, widowed persons and minorities had significantly lower prevalence odds; professionals had statistically significant and borderline lower prevalence odds for both VaD and AD; sales-service occupations had significantly lower odds for AD only. CONCLUSION: We observed variations in prevalence for AD and VaD in different regions and demographic groups in China that persisted after controlling for potential confounding factors. Sociodemographic factors are probable surrogates for conditions such as lifestyle, environment, comorbidities, and life expectancy.