1. Divison of Endocrinology, Department of Internal Medicine, National Health Insurance Service Ilsan Hospital, Goyang 10444, Republic of Korea
2. Divison of Endocrinology, Department of Internal Medicine, Keimyung University School of Medicine, Daegu 42601, Republic of Korea
3. Research and Analysis Team, National Health Insurance Service Ilsan Hospital, Goyang 10444, Republic of Korea
4. Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul 03722, Republic of Korea