Funding for this research was provided by:
Ministry of Health and Welfare (11-1352000-001549-01)
Received: 30 August 2018
Accepted: 16 November 2018
First Online: 29 November 2018
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of Seoul National University Hospital (IRB No: 1508–064-094). Online informed consents were obtained from all study participants before the survey.
: Not applicable.
: The authors declare that they have no competing interests.
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