Funding for this research was provided by:
National Science Foundation for youth (81801401)
Received: 3 June 2019
Accepted: 11 May 2020
First Online: 24 May 2020
Ethics approval and consent to participate
: Our study was approved by the ethics committee of Peking Union Medical College Hospital (Number of Ethics document: S-K471). This was a web-based questionnaire survey. The electronic version informed consents were signed by all the participants before they filled the questionnaire.
: Not applicable.
: The authors declare that they have no competing interests.