Received: 9 March 2020
Accepted: 26 May 2020
First Online: 30 June 2020
Ethics approval and consent to participate
: The study was approved by the Yonsei Severance Hospital Institutional Review Board (No. 4-2018-1143). KNHANES surveys are national open-access public data approved by the Korean Center for Disease Control and informed consent was obtained by participants and parents or legal representative of children under 14 which is approved by Korean law. The raw data from the KNHANES surveys are freely available at ExternalRef removed.
: Not applicable.
: The authors declare no competing interest associated with this report.