Are job strain and sleep disturbances prognostic factors for low-back pain?A cohort study of a general population of working age in Sweden.

The aim of this study was to determine whether job strain, i.e. a combination of job demands and decision latitude (job control), and sleep disturbances among persons with occasional low-back pain are prognostic factors for developing troublesome low-back pain; and to determine whether sleep disturbances modify the potential association between job strain and troublesome low-back pain. A population-based cohort from the Stockholm Public Health Cohort surveys in 2006 and 2010 (= 25,167) included individuals with occasional low-back pain at baseline 2006 (= 6,413). Through logistic regression analyses, potential prognostic effects of job strain and sleep disturbances were studied. Stratified analyses were performed to assess modification of sleep disturbances on the potential association between job strain and troublesome low-back pain. Those exposed to job strain; active job (odds ratio (OR) 1.3, 95% confidence interval (95% CI) 1.1-1.6), or high strain (OR 1.5, 95% CI 0.9-2.4) and those exposed to severe sleep disturbances (OR 3.0, 95% CI 2.3-4.0), but not those exposed to passive jobs (OR 1.1, 95% CI 0.9-1.4) had higher odds of developing troublesome low-back pain. Sleep disturbances did not modify the association between job strain and troublesome low-back pain. These findings indicate that active job, high job strain and sleep disturbances are prognostic factors for troublesome low-back pain. The odds of developing troublesome low-back pain due to job strain were not modified by sleep disturbance.