1. Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
2. Department of Internal Medicine, Inje University College of Medicine, Busan, Korea.
3. Department of Internal Medicine, Chonbuk National University Medical College, Jeonju, Korea.
4. Department of Internal Medicine, Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.
5. Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
6. Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
7. Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, Korea.
8. Department of Preventive Medicine, Dongguk University College of Medicine, Gyeongju, Korea.