- Correspondence to Professor Maigeng Zhou, National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Xicheng District, Beijing 100050, China; and Professor Zhengming Chen, Clinical Trial Service Unit & Epidemiological Studies Unit, University of Oxford;
- Received May 17, 2016
- Revised July 26, 2016
- Accepted July 27, 2016
- First published September 22, 2016.
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