1. Department of Preventive Medicine, Ajou University School of Medicine, Suwon, Republic of Korea
2. Department of Internal Medicine, Chungbuk National University Hospital and Chungbuk National University College of Medicine, Cheongju, Republic of Korea
3. Department of Internal Medicine, Nowon Eulji Medical Center, Eulji Hospital, Seoul, Republic of Korea
4. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
5. Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
6. Department of Internal Medicine, Mediplex Sejong Hospital, Incheon, Republic of Korea