Funding for this research was provided by:
National Natural Science Foundation of China (71774104, 71974117)
China Medical Board (16-257)
Cheeloo Youth Scholar Grant (IFYT1810)
Shandong University (2012DX006)
NHC Key Laboratory of Health Economics and Policy Research (NHC-HEPR2019014)
Received: 16 July 2020
Accepted: 1 February 2021
First Online: 6 February 2021
Ethics approval and consent to participate
: The protocol for this study was approved by the Ethical Committee of School of Public Health, Shandong University (approval number, 20181228). All participants gave their informed written consent for participation prior to the face-to-face interview. The data used in this study was anonymized before its use.
: Not applicable.
: The authors declare that they have no competing interests.