Funding for this research was provided by:
the National Key Research and Development Program Key Specialities of Precision Medicine, China (2017YFC0907001)
Received: 11 January 2019
Accepted: 5 June 2019
First Online: 13 June 2019
Ethics approval and consent to participate
: The ethics approval was exempted by Fudan University Institution Review Board. An informed consent paper was signed by each participant before the questionnaire interview.
: Not applicable.
: No competing interests.