A follow-up study of the incidence and risk factors of dementia in two communities in Beijing

Abstract

Objective To describe the incidence in population and urban-rural distribution of dementia in elderly people aged 65 years and over in two communities in Beijing and to explore potential psychosocial and cardiovascular risk factors of dementia. Methods This 5-year follow-up study was a part of the 10/66 dementia study.Two thousands and twenty five non-dementia people aged 65 years and over in Xicheng District (urban) and Daxing District (rural) of Beijing were followed up during February,2009 to March,2010.The study was a comprehensive one-stage survey and diagnosis of dementia was based on 10/66 dementia criteria.Measurements included the Community Screening Interview for Dementia,Geriatric Mental State-B3 version,Background Sociodemographic and Risk factor Questionnaire including self-report chronic diseases,Informant Interview Questionnaire,and physical examinations.Cox proportional hazard regression model was conducted to explore potential risk factors. Results One hundred and seventy three incident dementia patients were identified.The 5-year cumulative incidence rate of dementia was 8.54% and the average annual incidence rate was 1.77%.The rates increased consistently with aging.The incidence of dementia was higher in female than that in male,and the difference was statistically significant (2.00% vs.1.42%,P<0.01).The incidence of dementia among lower education level group was higher than those in higher level groups,and different marriage statuses had significantly different incidence of dementia (P<0.01).The incidence difference between urban and rural communities was not statistically significant.Multivariate Cox regression model showed that older age,smoking,bigger waist hip ratio and stoke history were risk factors of dementia,and physical exercise was protective factor of dementia. Conclusions The incidence of dementia in the study is higher than those in previous studies.It should be advocated to reduce smoking,prevent and treat stroke,and exercise physically in order to decrease risk of dementia. Key words: Dementia; Aged; Incidence; Risk factor