Received: 19 August 2019
Accepted: 27 February 2020
First Online: 4 March 2020
Ethics approval and consent to participate
: All participants were fully informed of the study aims and methods and written informed consent was obtained before the screening interview. The study was approved by the Institutional Review Board of Seoul National University Hospital (IRB No. 1807–135-961).
: Not applicable.
: The author(s) declare that they have no competing interests.