Received: 26 March 2020
Accepted: 25 August 2020
First Online: 29 August 2020
Ethics approval and consent to participate
: All participants signed a written informed consent form and the protocols for KNHANES were approved by the Institutional review board of the Korean Centers for Disease Control and Prevention (KCDC).
: Our manuscript contains no individual person’s data in any form.
: The authors declare that they have no competing interests.