Social inequalities in all-cause mortality among adults with multimorbidity: a 10-year prospective study of 0.5 million Chinese adults.

"Competing interests None declared."

"Funding This work was supported by the National Key Research and Development Program of China (2016YFC0900500, 2016YFC0900501, 2016YFC0900504). The CKB baseline survey and first resurvey were supported by a grant from the Kadoorie Charitable Foundation in Hong Kong. Long-term follow-up was supported by grants from the UK's Wellcome Trust (202922/Z/16/Z, 088158/Z/09/Z, 104085/Z/14/Z). This study's funders played no role in study design, data collection, data analysis, data interpretation or report writing."

"Data from the China Kadoorie Biobank (CKB) study, a large-scale prospective cohort of >0.5 million participants ages 30–79 y, was used for this study. Detailed information on CKB's study design, survey methods and population has been reported previously., The baseline survey occurred between 25 June 2004 and 15 July 2008 in 10 geographical areas (five urban and five rural, defined according to governmental administrative structure) of China. These areas were selected from China's nationally representative Disease Surveillance Points (DSPs) as maximizing regional and social diversity, levels of SES, exposure to certain risk factors, population stability, quality of death and disease registries and long-term local commitment to the project. Official local residential records were used to identify individuals eligible for this study (adults ages 30–79 y). All participants completed an interviewer-administered electronic questionnaire providing detailed information on their demographic and socio-economic characteristics, medical history and lifestyle factors. Physical measurements were also recorded and a blood sample collected for long-term storage. Overall, 512 715 individuals (including a small number of individuals outside the target age range) agreed to participate in the study. One participant was excluded from the study due to a very high number (≥16) of coexisting diseases, while two participants were excluded due to missing baseline body height or weight values. The final analyses included 512 712 individuals comprised of 210 203 (41.0%) men and 302 509 (59.0%) women (see Table )."