[1] Univ Occupat & Environm Hlth, Sch Med, Dept Publ Hlth, Kitakyushu, Fukuoka 807, Japan
[2] Asahi Kasei, Nobeoka Off Hlth Care Ctr, Nobeoka, Japan
[3] Asahi Kasei Chem, Mizushima Works Hlth Care Ctr, Okayama, Japan
[4] Univ Occupat & Environm Hlth, Occupat Hlth Training Ctr, Kitakyushu, Fukuoka 807, Japan
[5] Univ Occupat & Environm Hlth, Sch Med, Dept Orthopaed Surg, Kitakyushu, Fukuoka 807, Japan
[6] Univ Occupat & Environm Hlth, Sch Med, Dept Urol, Kitakyushu, Fukuoka 807, Japan