1. Division of Respirology, Department of Medicine, Inje University Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.
2. Department of Pathology, Inje University Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.
3. Department of Health Promotion Medicine, Ewha Womans University Mokdong Hospital, Ewha Womans University College of Medicine, Seoul, Korea.