Institution: | 1. Department of Respiratory Medicine, Faculty of Medicine, Hokkaido University, Sapporo, Japan;2. Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan;3. Department of Biostatistics, Graduate School of Medicine, Hokkaido University, Sapporo, Japan;4. Hokkaido Medical Research Institute for Respiratory Diseases, Sapporo, Japan |