One hundred eighty patients with acute low-back pain (LBP) were compared to 608 age- and sex-matched controls with regard to somatic and personality characteristics. The low-back-pain group had a fourfold increase (median) in sick-leave episodes for reasons other than spinal morbidity during the preceding 2 years. In the same period, the median number of episodes of sick leave for LBP was 1 in the patients and 0 in the controls. The mean number of days off for other reasons was 34 (median = 20.5) in the patients compared to 9 (median = 0) in the controls, and days off for LBP were 20 (median = 5) and 5 (median = 0), respectively. Analysis of other factors than those directly related to LBP disclosed significant differences in marital status and smoking habits between patients and controls. Furthermore, LBP patients estimated their work to be physically heavier. We conclude that medical intervention should focus not only on the spine, but also on a wide range of other aspects of the patient's situation. Even in the acute phase of LBP, the previous sick-leave records should be analyzed to provide adequate measures to prevent future sick leaves. Presently, the sociomedical costs for a subset of the population who repeatedly seek help for LBP are significantly higher than those for the non-LBP population.