Funding for this research was provided by:
National Natural Science Foundation of China (71603034)
Received: 11 August 2020
Accepted: 22 December 2020
First Online: 7 January 2021
Ethics approval and consent to participate
: The datasets that support this article are publicly available from the project of the CLHLS. It was approved by research ethics committees of Peking University (IRB00001052–13074). The datasets analyzed during the current study are available online (ExternalRef removed) from Peking University Open Research Data for researchers who meet the criteria for access to these de-identified data. No experimental interventions were performed.
: Not applicable.
: The authors declare no conflict of interest.