1. Division of Endocrinology and Metabolism, Department of Internal Medicine, Soonchunhyang University Hospital, Soonchunhyang University College of Medicine, Seoul 04401, Korea
2. Department of Biostatistics, Soonchunhyang University Hospital, Soonchunhyang University College of Medicine, Seoul 04401, Korea
3. Elim Thyroid Clinic, Seoul 06520, Korea