1 China Development Research Foundation, Beijing, China.
2 Centre for Global Health, Usher Institute, University of Edinburgh, Edinburgh, UK; School of Social Sciences, Monash University, Melbourne, VIC, Australia.
3 Harvard TH Chan School of Public Health, Harvard University, Boston, MA, USA.
4 China Center for Health Development Studies, Peking University, Beijing, China; School of Public Health, Peking University, Beijing, China; Institute for Global Health, Peking University, Beijing, China. Electronic address: [email protected].