1. Public Health Medical Service, Seoul National University Boramae Medical Center, Seoul, Korea.
2. Department of Preventive Medicine, University of Ulsan College of Medicine, Seoul, Korea.
3. Regional Cardiocerebrovascular Center, Chungnam National University Hospital, Daejeon, Korea.
4. Department of Public Health, Graduate School of Konyang University, Daejeon, Korea.
5. Department of Preventive Medicine, Chungnam National University School of Medicine, Daejeon, Korea.