1. Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
2. Department of Internal Medicine, School of Medicine, CHA University, Seongnam, Korea.
3. Department of Internal Medicine, Soonchunhyang University College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Chonbuk National University Medical School, Jeonju, Korea.
5. Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
6. Department of Internal Medicine, VHS Medical Center, Seoul, Korea.
7. Department of Internal Medicine, Soonchunhyang University College of Medicine, Gumi, Korea.
8. Department of Internal Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea.
9. Department of Internal Medicine, Dong-A University College of Medicine, Busan, Korea.
10. Department of Internal Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
11. Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
12. Department of Internal Medicine, Dongsan Hospital, Keimyung University School of Medicine, Daegu, Korea.
13. Department of Internal Medicine, Sungkyunkwan University school of medicine, Samsung Medical Center, Seoul, Korea.
14. Medical Research Collaborating Center, Seoul National University Hospital, Seoul, Korea.
15. Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea.