Xu, Jun-Fang
Wang, Pei-Cheng
Cheng, Feng
Funding for this research was provided by:
Beijing Science and Technology Planning Project (D171100006717002)
National Natural Science Foundation of China (71904171)
National Natural Science Foundation of China (71874100)
Article History
Received: 28 October 2019
Accepted: 24 February 2020
First Online: 10 March 2020
Ethics approval and consent to participate
: Written consent was sought and obtained from all the participants. The confidentiality of individuals was properly protected in the management of investigation and the processing of data. The study protocol and consent procedure were approved by Institutional Review Board for Human Subject Research, Research Centre for Public Health at Tsinghua University (20163000254).
: All authors have agreed with the content and approved the submission of the manuscript.
: The authors declare that they have no competing interests.