Received: 16 October 2017
Accepted: 27 February 2018
First Online: 5 March 2018
Ethics approval and consent to participate
: The study was approved by the Institutional Review Board of Soonchunhyang Bucheon Hospital, Soonchunhyang University College of Medicine, and the study protocol adhered to the tenets of the Declaration of Helsinki. Informed consent was obtained from each participant.
: Not applicable.
: The authors declare that they have no competing interests.
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