1. Department of Family Medicine, Pusan National University Hospital, Busan, Korea
2. Biomedical Research Institute, Pusan National University Hospital, Busan, Korea
3. Department of Family Medicine, Pusan National University School of Medicine, Yangsan, Korea
4. Department of Medical Education, Pusan National University School of Medicine, Yangsan, Korea
5. Department of Family Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea