Funding for this research was provided by:
Ministry of Health & Welfare, Republic of Korea (HI16C0628)
Text and Data Mining valid from 2018-05-09
Received: 9 August 2017
Accepted: 19 April 2018
First Online: 9 May 2018
Ethics approval and consent to participate
: The study was approved in accordance to the requirements of the Ethics Committee at Cheil General Hospital (#CGH-IRB-2011-85). Written informed consent was obtained from all participants in compliance with the Declaration of Helsinki.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.