1. Department of Internal Medicine, Inha University College of Medicine, Incheon, Korea.
2. Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Biomedical Sciences, Inha University College of Medicine, Incheon, Korea.
4. Department of Endocrinology and Metabolism, Kyung Hee University School of Medicine, Seoul, Korea.
5. Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
6. Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, Korea.