Funding for this research was provided by:
National Research Foundation of Korea (2015R1A1A1A05001209)
Korea National Institute of Health (1420080)
Received: 6 December 2018
Accepted: 18 August 2019
First Online: 28 August 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board (IRB) of Yonsei University Severance Hospital. Informed consent form was waived by the IRB.
: The authors declare that they have no competing interests.
: Not applicable.