1. Department of Social and Preventive Medicine, Inha University School of Medicine, Incheon, Korea.
2. Department of Occupational and Environmental Medicine, Inha University School of Medicine, Incheon, Korea.
3. Department of Pulmonary and Critical Care Medicine, Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
4. Department of Social and Preventive Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea.
5. Department of Thoracic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. Center for Lung Cancer, Inha University Hospital, Inha University School of Medicine, Incheon, Korea.