[1] Univ Hong Kong, Sch Publ Hlth, Hong Kong, Hong Kong, Peoples R China
[2] Univ Hong Kong, Dept Med, Hong Kong, Hong Kong, Peoples R China
[3] Guangzhou 12 Hosp, Guangzhou, Guangdong, Peoples R China
[4] Univ Birmingham, Publ Hlth Epidemiol & Biostat, Birmingham B15 2TT, W Midlands, England