Funding for this research was provided by:
the research project of Ningxia Medical University (No. XT2019009)
the key research and development project of Ningxia Autonomous Region (No. 2021BEG02030)
Article History
Accepted: 11 August 2022
First Online: 25 August 2022
Declarations
:
: The authors have no conflicts of interest to disclose.
: The CFPS is a nationally representative, biennial household survey that has been performed since 2010, organized by the Institute of Social Science Survey, Peking University. The Peking University Biomedical Ethics Review Committee provided ethical approval for the survey (Approval number: IRB00001052-14010).