1. Department of Public Health, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan;
2. Division of Respiratory Diseases, Department of Medicine, Kawasaki Medical School, Okayama, Japan;
3. Second Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan;
4. Department of Molecular Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA;
5. Respiratory Medicine, National Hospital Organization Nanao Hospital, Nanao, Japan;
6. Department of Environmental and Preventive Medicine, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan