Song, Huan
Ji, Kehan
Sun, Tao
Article History
Received: 21 May 2021
Accepted: 1 December 2021
First Online: 12 January 2022
Declarations
:
: The present study is a secondary analysis using the CLHLS data. The CLHLS study was approved by the Biomedical Ethics Committee of Peking University (IRB00001052–13074). Informed consent was signed by all participants or their legal representatives in the baseline and follow-up surveys. All methods were performed in accordance with national law and the Helsinki Declaration of 1975 and its later amendments.
: Not applicable.
: The authors declare that they have no competing interests.