Received: 5 July 2020
Accepted: 3 February 2022
First Online: 21 February 2022
: This study was approved by the institutional review board of Ningxia Medical University (document number: 2020112). Participants provided informed consent online: participants were asked to check the box on their device’s screen with the response of their choice (i.e. ‘I agree to participate in the survey’ or ‘I do not agree to participate in the survey’). If they checked ‘I do not agree’, the computer program terminated automatically.All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Not applicable.
: The authors declare that they have no competing interests.