In 1995, about 600,000 patients with occupational diseases and trauma were recorded by Ministry of Labour in Japan. Among them, 9,230 patients were compensated for absence from work due to occupational injury or disease for 4 days and over. The most common cause was that due to traumatic injuries (6,451 cases, including 5,035 cases with accidental low back pain). The remaining cases were pneumoconiosis and its complications (1,326 cases), diseases due to abnormal temperatures (699 cases), diseases due to chemicals (311 cases), and so on (Ministry of Labour, 1996). The number of reported occupational injuries and diseases has gradually decreased in recent years.