Funding for this research was provided by:
National Research Foundation of Korea (NRF-2016R1A6A3A11932432, NRF-2018R1D1A1B07048153)
Text and Data Mining valid from 2019-05-03
Received: 22 August 2018
Accepted: 18 April 2019
First Online: 3 May 2019
Ethics approval and consent to participate
: Prior to the interview, written informed consent was given by all participants of the LPOPS survey. The data were anonymized and de-identifiable with no personal information, with careful protection on confidentiality. The Institutional Review Board (IRB) of the Keimyung University reviewed and approved the study protocol in accordance with the Declaration of Helsinki.
: No applicable.
: All the authors declare that they have no competing interests.
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