1 Institute of Social Medicine, School of Public Health, Zhejiang University School of Medicine, Hangzhou, China.
2 Vanke School of Public Health, Tsinghua University, Beijing 100084, China.
3 Vanke School of Public Health, Tsinghua University, Beijing 100084, China; Institute for Healthy China, Tsinghua University, Beijing 100084, China.
4 Vanke School of Public Health, Tsinghua University, Beijing 100084, China; Institute for Healthy China, Tsinghua University, Beijing 100084, China. Electronic address: liangwn@tsinghua.edu.cn.