Occupational causes of low-back pain.

Associations between occupational activities and low-back pain (LBP) were examined in a retrospective postal survey of 545 randomly selected adults. Each subject gave a lifetime occupational history on six specified physical activities and also a lifetime history of LBP. Among the 436 subjects answering the questionnaire, the lifetime incidence of LBP was 63%. The occurrence of LBP was related by Cox's proportional hazards regression model to occupational activities in the year prior to the onset of symptoms. For the men the strongest associations were with heavy lifting and prolonged car driving. There was also an association with heavy lifting among the women. These risks were exaggerated in the subset of subjects whose LBP followed a chronic unremitting course. The findings are consistent with previous reports linking LBP with manual materials handling and driving at work. However, in this sample, less than 20% of the cases could be attributed to such activities.