Job exposures as correlates of recovery in population-based rehabilitation intervention for work-related low back disorders

PURPOSE: Evaluating the impact of population-based rehabilitation interventions for work-related low back disorders (WR-LBD) requires job exposure factors to be considered as time-varying covariates. The role of job factors in recovery has not been well-established as most studies are based upon clinic samples, not working populations. This report represents the initial exploration of variables to be included in modeling job exposures as time-varying covariates of a study of work-place based rehabilitation intervention. METHODS: The study sample consisted of 162 hourly production employees from two automotive plants with work-related low back disorder not due to external trauma. Data reported herein were collected at baseline from an on-going large randomized clinical trial of rehabilitation for WR-LBD. Low back pain as measured by the North American Spine Society Baseline Form was examined in relation to: self-reported job factors from the Job Content Questionnaire and job risk category for low back disorder determined by the Lumbar Motion Monitor (LMM), an electronic goniometer which transmits back motion signals to a computer for analysis. RESULTS: Low back pain, with and without leg pain, was not found to be associated with hours worked in the previous week, job shift, perceptions of the pace of the job, or job risk of low back disorder as measured by the LMM. Low back pain was significantly (p < 0.05) correlated with perceptions of: how hard the work was, how much physical effort was required, how hectic the job was, whether or not there was sufficient time to do the job, and how much concentration and physical effort were required for the job. CONCLUSIONS: Self-report of perceptions of job strain may be as important, if not more important, than current quantitative factors thought to influence recovery from work-related low back pain.