Funding for this research was provided by:
National Research Foundation of Korea (NRF-2012R1A1A4A01012884)
Received: 26 July 2019
Accepted: 4 June 2020
First Online: 30 June 2020
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of Yonsei University Wonju College of Medicine with reference number of YWMR-12-0-015. We obtained written informed consent from each participant and his legal guardian. Participation was voluntary, and Participants could withdraw at any time from the study.
: Not applicable.
: The authors declare no conflict of interest.