1. Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
2. Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Catholic University of Korea College of Medicine, Seoul, Korea.
4. Department of Health Promotion Center, Seoul St. Mary's Hospital, Seoul, Korea.
5. Department of Internal Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
6. Department of Internal Medicine, Soonchunhyang University College of Medicine, Cheonan, Korea.
7. Department of Internal Medicine, Hallym University College of Medicine, Seoul, Korea.
8. Department of Internal Medicine, Chonnam National University School of Medicine, Gwangju, Korea.
9. Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Korea.
10. Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea.
11. Department of Internal Medicine, Digestive Digestive Research Institute, Wonkwang University College of Medicine, Iksan, Korea.
12. Department of Internal Medicine, Inje University College of Medicine, Busan, Korea.
13. Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.
14. Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Korea.
15. Chungbuk National University College of Medicine, Cheongju, Korea.
16. Department of Internal Medicine, Gangneung Asan Hospital, Gangneung, Korea.
17. Cancer Prevention Center, Korean National Cancer Center, Ilsan, Korea.
18. Department of Internal Medicine, Kwangju Christian Hospital, Gwangju, Korea.
19. Department of Internal Medicine, Eulji University College of Medicine, Daejeon, Korea.
20. Department of Internal Medicine, Kyung Hee University College of Medicine, Seoul, Korea.
21. Department of Internal Medicine, SMG-SNU Boramae Medical Center, Seoul, Korea.
22. Department of Internal Medicine, Keimyung University College of Medicine, Daegu, Korea.
23. Health Promotion Center, Inha University College of Medicine, Incheon, Korea.
24. Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, Korea.
25. Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.
26. Department of Internal Medicine, Busan National University College of Medicine, Busan, Korea.
27. Department of Internal Medicine, Kyungsang National University College of Medicine, Jinju, Korea.
28. Department of Internal Medicine, Chonbuk National University School of Medicine, Jeonju, Korea.
29. Department of Internal Medicine, Kunyang University College of Medicine, Daejeon, Korea.
30. Cheju Halla General Hospital, Jeju, Korea.
31. Hanmaeum Hospital, Jeju, Korea.
32. Health Promotion Center, Seoul National University Bundang Hospital, Seongnam, Korea.
33. Department of Internal Medicine, Dankook University College of Medicine, Cheonan, Korea.
34. Department of Internal Medicine, Chosun University College of Medicine, Gwangju, Korea.
35. Department of Internal Medicine, Dongguk University College of Medicine, Gyeongju, Korea.
36. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.