Funding for this research was provided by:
National Research Foundation of Korea (2015M3C7A1028926)
Basic Science Research Program through the National Research Foundation of Korea (NRF-2015R1A2A2A01004501)
Promising-Pioneering Researcher Program through Seoul National University (Promising-Pioneering Researcher Program through Seoul National University (SNU))
Received: 24 January 2020
Accepted: 30 July 2020
First Online: 6 August 2020
Ethics approval and consent to participate
: Both study protocols were approved by the Institutional Review Board of Seoul National University Hospital. Written informed consent was obtained from parents, and sufficient explanation of the study prior to enrollment was provided to all parents and youths.
: Not applicable.
: The authors declare that they have no competing interests.