Text and Data Mining valid from 2019-02-28
Received: 21 June 2018
Revised: 11 October 2018
Accepted: 15 October 2018
First Online: 28 February 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: The CHARLS study data are publicly available and are open to researchers all over the world. The current study is a secondary analysis of the deidentified CHARLS study data. The Institutional Review Boards at the University of Georgia granted the current study exemption from review.