Funding for this research was provided by:
National Natural Science Foundation of China (81973143)
Article History
Received: 31 January 2023
Accepted: 24 May 2023
First Online: 6 June 2023
Declarations
:
: Ethical approval for all the CHARLS waves was granted by the Institutional Review Board at Peking University. The IRB approval number for the main household survey, including anthropometrics, is IRB00001052-11015. During the fieldwork, each respondent who agreed to participate in the survey was asked to sign two copies of informed consent; one copy was kept in the CHARLS office, which was also scanned and saved in PDF format. For each illiterate or vulnerable participant, informed consent was obtained from a parent and/or legal guardian. All methods in this study were performed in accordance with the guidelines of the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.