1. Division of Endocrinology and Metabolism, Department of Medicine, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Korea.
2. Division of Endocrinology and Metabolism, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea.
5. Department of Internal Medicine, Chonbuk National University Hospital, Jeonju, Korea.
6. Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
7. Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
8. Department of Internal Medicine, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea.
9. Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Korea.