The National Health Insurance System-National Sample Cohort (NHIS-NSC) was utilized for this study after approval by health insurance review and assessment service (HIRA).

Individual data linkage of population was made internally in the Big Data Steering Department of the National Health Insurance Service. The authors of the study were approved to use customized tables via virtual terminal connected to personal computer after review of study proposal by HIRA for less than 6 months. By law, sharing a raw data or copying the data including photo copy is strictly banned. Therefore, we could not upload raw data in Plos One submission system. I added dataset as supporting information, but raw data could not be included. Any research who had interest in this study can request the use of NHIS-NSC by following the procedures outlined at homepage of HIRA (https://opendata.hira.or.kr/op/opc/selectPatDataAplInfoView.do). There is a cost for the use of virtual terminal. (XLSX)