Funding for this research was provided by:
Yonsei University College of Medicine (6-2018-0174 and 6-2017-0157)
Received: 2 March 2020
Accepted: 30 September 2020
First Online: 27 October 2020
Ethics approval and consent to participate
: Not applicable, as Korea Institute for Health and Social Affairs provides the Korea Welfare Panel Study data in the public domain.
: Not applicable.
: The authors declare that they have no competing interests.