1. Department of Preventive Medicine, School of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea
2. Department of Medical Education and Medical Humanities, School of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea
3. Cancer Policy Branch, National Cancer Control Institute, National Cancer Center, Goyang 410-769, Republic of Korea
4. Department of Preventive Medicine, College of Medicine, Korea University, Seoul 136-701, Republic of Korea