1. Department of Internal Medicine, Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.
2. Division of Endocrinology and Metabolism, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
3. Department of Endocrinology, Dongnam Institute of Radiological and Medical Sciences Cancer Center, Busan, Republic of Korea.
4. Division of Endocrinology and Metabolism, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
5. Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
6. Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea.