Zhao, Jinhui http://orcid.org/0000-0003-2166-5370
Sun, Hongpeng http://orcid.org/0000-0001-9382-5586
Ma, Yana http://orcid.org/0000-0002-4440-1928
Cheng, Xingxue http://orcid.org/0000-0001-8688-8167
Article History
Received: 18 March 2020
Accepted: 19 May 2020
First Online: 9 June 2020
Compliance with ethical standards
:
: The authors declare that they have no competing interests.
: Research ethics committee review and approval were not required, as the public files of the CHARLS and the CADUMS/CTADS were analyzed from the Research Data Centre (RDC) of Statistics Canada at the University of Victoria. No personal data are available from these public databases.