Funding for this research was provided by:
Korean Ministry of Health and Welfare, Korea Healthcare Technology R&D project (Grant number HI12C0035)
National Research Foundation of Korea (NRF- 2014R1A1A3049818)
Received: 24 February 2017
Accepted: 28 March 2018
First Online: 11 April 2018
Ethics approval and consent to participate
: Institutional Review Board of Seoul National University College of Medicine provided ethical approval of this study. All participants were fully informed of the study objectives, and written consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.