Study design, setting and sample
This 6-year longitudinal observational study was based on the territory-wide community cohort of the Elderly Health Centres (EHCs) of the Department of Health of the Government of Hong Kong, which has been reported elsewhere8. Briefly, our cohort consisted of 18,298 individuals aged 65 years or older from all 18 districts in Hong Kong at inception. All participants completed standardized clinical assessment of cognitive status and comprehensive evaluation of a wide range of physical and mental health problems, lifestyle behaviours, and sociodemographic factors at the EHCs at baseline. They have since then been followed yearly at the EHCs. In this study, those who missed follow-up were actively traced and interviewed, and written informed consent was obtained from all the participants of the study, or from the Legally Authorized Representatives if they…
