Funding for this research was provided by:
Ministry of Education - Singapore (R-101-000-084-112)
Received: 17 August 2020
Accepted: 18 November 2020
First Online: 10 December 2020
Ethics approval and consent to participate
: The data from TVS2014 obtained the ethical approval by the research ethics committee of Shanghai University of Finance and Economics (SUFE). The data used in this study was anonymized before its use, and the authors got a permission for use from SUFE.
: Not applicable.
: D.G. is a Senior Editorial Board Member of BMC Geriatrics. Q.F. is an Editorial Board Member of BMC Geriatrics.