Funding for this research was provided by:
National Natural Science Foundation of China (81602869)
Fundamental Research Funds for the Central Universities (3104221)
Received: 23 November 2020
Accepted: 2 June 2021
First Online: 10 June 2021
: The Biomedical Ethics Review Committee of Peking University approved the China Health and Retirement Longitudinal study, and all interviewees were required to provide informed consent. The ethical approval number was IRB00001052–11015.
: Not applicable.
: The authors declare that they have no competing interests.