1. Department of Health Behavior and Social Medicine, West China School of Public Health and West China Fourth Hospital, Sichuan University, No. 16 South Renmin Road 3 Section, Chengdu 610041, China
2. Freeman Spogli Institute for International Studies, Stanford University, Stanford, CA 94305, USA
3. Department of Public Health, Erasmus University Medical Center, 3000 CA Rotterdam, The Netherlands