1. Department of Family Medicine, Hanyang University College of Medicine, Seoul, Korea.
2. Department of Preventive Medicine/Institute of Community Health, Hanyang University College of Medicine, Seoul, Korea.
3. Department of Preventive Medicine, Dong-A University College of Medicine, Busan, Korea.
4. Graduate School of Public Health, Seoul National University, Seoul, Korea.
5. Division of Cardiology, Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea.