1. Department of Internal Medicine, The Catholic University of Korea College of Medicine, Seoul, Korea.
2. Division of Endocrinology and Metabolism, Department of Internal Medicine, St. Vincent's Hospital, The Catholic University of Korea College of Medicine, Suwon, Korea.
3. Division of Endocrinology and Metabolism, Department of Internal Medicine, Yeouido St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea.
4. Department of Preventive Medicine, The Catholic University of Korea College of Medicine, Seoul, Korea.
5. Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea.