1. Department of Health Promotion, Yonsei University College of Medicine, Seoul, Korea.
2. Division of Cardiology, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
3. Division of Cardiology, Department of Internal Medicine, Dongsan Medical Center, Keimyung University College of Medicine, Daegu, Korea.
4. Division of Cardiology, Department of Internal Medicine, Ewha Womans University Seoul Hospital, Seoul, Korea.