1. Department of Internal Medicine, Cardiovascular and Metabolic Disease Center, Inje University Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.
2. Division of Endocrinology and Metabolism, Department of Internal Medicine, Myongji Hospital, Goyang, Korea.
3. Division of Endocrinology and Metabolism, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
5. Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea.
6. Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, Korea.