1. Department of Respiratory Medicine, Hiroshima Prefectural Hospital, Hiroshima, Japan
2. Department of Respiratory Medicine, JA Onomichi General Hospital, Onomichi, Japan
3. Department of Respiratory Medicine, National Hospital Organization Higashihiroshima Medical Center, Higashihiroshima, Japan
4. Department of Internal Medicine, Mihara Medical Association Hospital, Mihara, Japan
5. Department of Respiratory Medicine, Hiroshima University Hospital, Hiroshima, Japan