1. Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
3. Division of Cardiology, Department of Internal Medicine, Heart Center, Konyang University Hospital, Daejeon, Korea.
4. Department of Cardiovascular Medicine, Gachon University Gil Medical Center, Incheon, Korea.
5. Gachon Cardiovascular Research Institute, Gachon University, Incheon, Korea.