Funding for this research was provided by:
Korea Health Industry Development Institute (HI18C1111)
Text and Data Mining valid from 2019-01-30
Received: 20 June 2018
Revised: 12 December 2018
Accepted: 11 January 2019
First Online: 30 January 2019
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.
: Informed consent was obtained from all individual participants included in the study.