Published on in Vol 21, No 7 (2019): July
Preprints (earlier versions) of this paper are
available at
https://preprints.jmir.org/preprint/14210, first published
.
1 Department of Global Health, School of Public Health, Peking University, Beijing, China
2 Department of Public Health, Shihezi University School of Medicine, Xinjiang, China
3 China Center for Health Development Studies, Peking University, Beijing, China