Funding for this research was provided by:
Ministry of Health and Welfare (HI13C0729)
Text and Data Mining valid from 2018-09-15
Received: 19 February 2018
Accepted: 7 September 2018
First Online: 15 September 2018
Ethics approval and consent to participate
: This study was approved by the institutional review board of KCDC (2013-07CON-03-4C, 2013-12EXP-03-5C), and informed consent to participate in the study was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
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