Funding for this research was provided by:
Catholic University of Korea
Received: 28 January 2020
Accepted: 10 August 2020
First Online: 14 August 2020
Ethics approval and consent to participate
: The survey protocol of KNHANES was approved by the KCDC Institutional Review Board until 2014, and has been conducted without deliberation according to the bioethics law since 2015 (2013-07CON-03-4C and 2013-12EXP-03-5C). Informed consent was obtained from all participants.
: Not applicable.
: All authors declare no potential conflict of interest.