Funding for this research was provided by:
National Natural Science Foundation of China (71704042)
Received: 19 February 2019
Accepted: 31 May 2019
First Online: 10 June 2019
Ethics approval and consent to participate
: We got data from CHARLS project. The CHARLS project team filed an ethical review application to Ethical Review Committee (IRB) at Peking University in January 2011. After a revision of the Informed Consent section, the survey obtained approval.During the CHARLS field work, every respondent who agreed to participate in the survey had to sign the informed consent in two copies, the paper material was kept in CHARLS office, which was also scanned and saved in PDF format for checking later by IRB if necessary. Four separate consents were obtained: one for the main field work, one for the non-blood biomarkers and one for taking of the blood samples and another for storage of blood for future analyses.On the CHARLS homepage, we applied for their data online. After online review by the CHARLS TEAM, they gave us permission to download and use CHARLS 2015 data.
: Not applicable.
: The authors declare that they have no competing interests.