Funding for this research was provided by:
National Natural Science Foundation of China (71573049)
Received: 28 January 2019
Accepted: 26 March 2019
First Online: 5 April 2019
Ethics approval and consent to participate
: This study protocol version 4.0 dated 4 December 2018 has obtained ethical approval (IRB#2018-01-0663) from the Medical Research Ethics Committee, School of Public Health, Fudan University. All participants will provide informed written consent prior to commencing the study.
: Not applicable.
: The authors declare that they have no competing interests.
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