Incidence of dementia and subtypes: A cohort study in four regions in China

INTRODUCTION: There is a dearth of literature on the incidence of dementia in China. METHODS: Using a stratified, multistage, cluster-sampling method, 16,921 nondemented participants ≥55 years were recruited from four regional centers in China in 1997 and followed up to 4.5 years. Cases were identified through a three-step protocol, according to standardized criteria for dementia, Alzheimer's dementia (AD), and vascular dementia (VaD). RESULTS: The crude incidence in persons ≥65 years was 12.1/1000 person-years for dementia, 8.2/1000 person-years for AD, and 3.1/1000 person-years for VaD. After adjusting for sociodemographic factors, older age and lower education were associated with a higher risk of incident dementia, AD and VaD; regional difference was associated mainly with incidence of VaD (north vs. south: hazard ratio [HR] = 3.59); modestly with AD (east vs. west: HR = 1.55). DISCUSSION: The incidence of dementia in Chinese population is comparable with that in Europe and United States.