1. Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
3. Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Bucheon St. Mary’s Hospital, The Catholic University of Korea, Bucheon, Korea.