1. Department of Internal Medicine, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea.
2. Department of Cardiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University College of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
5. Department of Internal Medicine, Kangbuk Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. Department of Internal Medicine, Chungnam National University Sejong Hospital, Chungnam National University College of Medicine, Sejong, Korea.
7. Department of Internal Medicine, Research Institute of Clinical Medicine of Jeonbuk National University, Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Korea.
8. School of Biosystem and Biomedical Science, Korea University College of Health Science, Seoul, Korea.
9. Department of Endocrinology and Metabolism, Kyung Hee University Hospital at Gangdong, Kyung Hee University College of Medicine, Seoul, Korea.