Sichuan University, Sichuan University, Sichuan University, affiliation not provided to SSRN, Sichuan University, Tibet Center for Disease Control and Prevention, Yunnan University, Sichuan University, Sichuan University, Sichuan University, Sichuan University, Sichuan University - West China School of Public Health, Sichuan University, Sichuan University, Sichuan University, Sichuan University, Sichuan University, Sichuan University - West China School of Public Health, Sichuan University - West China School of Public Health, affiliation not provided to SSRN, Sichuan University and Sichuan University - Department of Epidemiology and Biostatistics