1. Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
2. Division of Endocrinology and Metabolism, Inha University Hospital, Inha University School of Medicine, Incheon, Republic of Korea
3. Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
4. Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA