Article History
Received: 1 December 2022
Accepted: 27 February 2023
First Online: 18 March 2023
Competing interests
: The authors declare no competing interests.
: This study used open data. Ethical approval for this type of study is not required by our institute. The CHARLS survey was approved by the Ethical Review Committee of Peking University.
: In the data collection of the CHARLS survey, all participants signed the informed consent at the time of participation.