Funding for this research was provided by:
National Research Foundation of Korea (2020R1F1A1070468, 2021M3E5D1A0101517621)
Ministry of Trade, Industry and Energy (KMDF_PR_20200901_0214-2021-03)
Received: 24 March 2021
Accepted: 31 July 2021
First Online: 9 August 2021
: The study was conducted following the Helsinki declaration and approved by the Institutional Review Board (IRB) of the KCDC (IRB: 2010-02CON-21-C, 2011-02CON-06-C, 2012-01EXP-01-2C, 2013-07CON-03-4C, 2013-12EXP-03-5C, and 2018–01-03-P-A). Before analysis, all data were anonymized, and voluntary informed written consent was obtained from all KNHANES participants.
: Not applicable.
: The authors declare that they have no competing interests.