Kim, Na-Rae
Kim, Ko-Woon
Kim, Ha-Na
Song, Sang-Wook
Article History
Received: 23 March 2017
Accepted: 7 May 2017
First Online: 15 May 2017
Compliance with Ethical Standards
: All protocols were approved by the Institutional Review Board of the KCDC, and all participants provided written informed consent at baseline.
: The authors declare that they have no conflicts of interest.