Received: 2 December 2019
Accepted: 8 June 2020
First Online: 20 July 2020
Ethics approval and consent to participate
: This study received approval from the institutional review board of Pusan National University (PNU 2016–122-HR). The authors obtained all necessary administrative permission to access the data prior to conducting this study. Participants’ information was anonymized and de-identified by the Korea Institute for Health and Social Affairs and the Seoul National University Institute for Social Welfare according to Korean privacy law.
: Not applicable.
: The authors declare that they have no competing interests.