1. Department of Internal Medicine, School of Medicine, Kangwon National University, Chuncheon, Korea.
2. Department of Internal Medicine, Soonchunhyang University Gumi Hospital, Gumi, Korea.
3. Division of Endocrinology and Metabolism, Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea.
4. Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine, Ansan, Korea.
5. Department of Internal Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.