Funding for this research was provided by:
Health Promotion Administration, Ministry of Health and Welfare (HI13C1204, HI16C1559)
Received: 6 May 2020
Accepted: 6 November 2020
First Online: 27 November 2020
Ethics approval and consent to participate
: The protocol was approved by the institutional review board (No. 2013-04-41) of CHA Bundang Medical Center and the Korean Ministry of Food and Drug Safety (No. 12515). Parents or representatives of all participant (age under 6 years or below) provided written informed consent to participate in the study.
: Consent for publication is not applicable for this manuscript.
: The authors declare no potential conflicts of interest.