Published on in Vol 6, No 1 (2018): January
1 The George Institute for Global Health, Peking University Health Science Center, Beijing, China
2 School of Public Health, Peking University Health Science Center, Beijing, China
3 School of Public Health, Hebei Medical University, Shijiazhuang, China
4 Faculty of Medicine, University of New South Wales, Sydney, Australia
*these authors contributed equally