Cohort profile: Beijing Healthy Aging Cohort Study (BHACS).

The Beijing Healthy Aging Cohort Study (BHACS) was established to supplement the limited data of a large representative cohort of older people based on the general population and was designed to evaluate the prevalence, incidence, and natural history of cognitive decline, functional disability, and conventional vascular risk factors. The aim was to determine the evolution of these conditions by estimating the rates and determinants of progression and regression to adverse outcomes, including dementia, cardiovascular events, cancer, and all-cause death. It can therefore provide evidence to help policy makers develop better policies to promote healthy aging in China. BHACS consisted of three cohorts (BLSA, CCHS-Beijing, and BECHCS) in Beijing with a total population of 11 235 (6281 in urban and 4954 in rural areas) and an age range of 55 years or older (55-101 years) with a mean age of 70.35 ± 7.71 years (70.69 ± 7.62 years in urban and 69.92 ± 7.80 years in rural areas). BHACS-BLSA conducted the baseline survey in 2009 with a multistage stratification-random clustering procedure for people aged 55 years or older; BHACS-CCHS-Beijing conducted the baseline survey in 2013-2015 with a stratified multistage cluster random sampling method for people aged 55 years or older; and BHACS-BECHCS conducted the baseline survey in 2010-2014 with two-stage cluster random sampling method for people aged 60 years or older. Data were collected through questionnaires, physical measurements, and laboratory analyses. Topics covered by BHACS include a wide range of physical and mental health indicators, lifestyles and personal, family, and socio-economic determinants of health. There are no immediate plans to make the cohort data freely available to the public, but specific proposals for further collaboration are welcome. For further information and collaboration, please contact the corresponding author Yao He (e-mail: yhe301@x263.net).