1. Department of Respiratory Medicine, University of Occupational & Environmental Health, Japan, 1–1, Iseigaoka, Yahatanishiku, Kitakyushu, Fukuoka 807–8555, Japan
2. Department of Clinical Nursing, University of Occupational & Environmental Health, Japan, 1–1, Iseigaoka, Yahatanishiku, Kitakyushu, Fukuoka 807–8555, Japan