1 Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, Renmin South Road 16, Chengdu, 610041, Sichuan, People's Republic of China. mengqiaowang@gmail.com.
2 Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, Renmin South Road 16, Chengdu, 610041, Sichuan, People's Republic of China.
3 Department of Population Health Science, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA, 30912, USA. yshi@augusta.edu.
4 Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, Renmin South Road 16, Chengdu, 610041, Sichuan, People's Republic of China. zhaoxing731@gmail.com.