1. Division of Endocrinology and Metabolism, Hallym University College of Medicine, Chuncheon, Korea.
2. Department of Internal Medicine, Graduate School, Hanyang University, Seoul, Korea.
3. Department of Internal Medicine, CM Hospital, Seoul, Korea.
4. Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea.
5. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.