1. Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Inje University Haeundae Paik Hospital, Busan, Korea.
3. Department of Medicine, Cheil General Hospital & Women's Healthcare Center, Kwandong University College of Medicine, Seoul, Korea.
4. Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, Korea.
5. Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea.
6. Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea.
7. Department of Endocrinology and Metabolism, Kyung Hee University School of Medicine, Seoul, Korea.