Funding for this research was provided by:
National Research Foundation of Korea (NRF-22B20152813529)
Article History
First Online: 31 August 2018
Compliance with Ethical Standards
:
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The data has been nationally approved (Nationally Approved Statistics No. 117079).
: Informed consent was obtained from all individual participants included in the study.