Funding for this research was provided by:
National Health Commission of China (2018)
Received: 11 February 2020
Accepted: 25 February 2021
First Online: 5 March 2021
: The Ethics Committee (IRB) in the Public Health School of Peking Union Medical College approved the study protocol.
: Before responding to the questionnaires of the survey, all participants signed the informed consent.
: The authors declare no conflict of interest.