1. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, University of Ulsan College of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Inje University College of Medicine Ilsan Paik Hospital, Goyang, Korea.
4. Department of Internal Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea.
5. Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
6. Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
7. Department of Internal Medicine, The Catholic University of Korea College of Medicine, Suwon, Korea.
8. Department of Surgery, Hallym University College of Medicine, Chuncheon, Korea.
9. Center for Preventive Medicine and Public Health, Seoul National University Bundang Hospital, Seongnam, Korea.