1. Department of Internal Medicine, Korea University Medical Center Guro Hospital, Seoul, Korea
2. Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
3. Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea
4. Department of Internal Medicine, Dongguk University Ilsan Hospital, Goyang, Korea
5. Department of Internal Medicine, Kyung Hee University Medical Center, Seoul, Korea
6. Department of Internal Medicine, The Catholic University of Korea, Seoul St. Mary’s Hospital, Seoul, Korea
7. Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Korea
8. Research Institute of Salt and Health, Seoul, Korea
9. Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea