1. From the Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom (HD, DB, GW, RC, L-SH, RP, and ZC); the Chinese Academy of Medical Sciences, Dongcheng District, Beijing, China (LL, YG, and ZB); the School of Public Health, Peking University, Beijing, China (LL); the Chinese Center for Disease Control and