1. Department of Family Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea
2. Department of Family Medicine, Pusan National University Hospital, Busan, Korea
3. Biomedical Research Institute, Pusan National University Hospital, Busan, Korea
4. Busan Tobacco Control Center, Pusan National University Hospital, Busan, Korea
5. Departments of Family Medicine, Pusan National University School of Medicine, Yangsan, Korea
6. Departments of Medical Education, Pusan National University School of Medicine, Yangsan, Korea