1. Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
2. Chaum Life Center, CHA University School of Medicine, Seoul, Korea.
3. Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Dongtan Jeil Women's Hospital, Hwasung, Korea.
5. Department of Laboratory Medicine, Kosin University College of Medicine, Busan, Korea.