Text and Data Mining valid from 2019-09-17
Received: 1 November 2018
Accepted: 9 September 2019
First Online: 17 September 2019
Ethics approval and consent to participate
: Ethical approval was obtained from the Seoul National University Boramae Medical Center Institutional Review Board prior to the start of the study. All participants provided informed, written consent.
: Not applicable.
: The authors declare that they have no competing interests.