aTokyo College, The University of Tokyo, Tokyo, Japan

bThe University of North Carolina Project China, Guangzhou, China

cJane Addams College of Social Work, University of Illinois, Chicago, Illinois, USA

dSaw Swee Hock School of Public Health, National University of Singapore, Singapore

eDepartment of Social Medicine and Health Education, School of Public Health of Nanjing Medical University, Nanjing, China

Correspondence to Dan Wu, Professor, 101 Longmian Avenue, Jiangning District, Nanjing 211166, China. E-mail: [email protected]