Objectives: This study aimed at developing a model for determining the work-relatedness of low-back pain for a worker with low-back pain using both a personal exposure profile for well-established risk factors and the probability of low-back pain if the worker were unexposed to these factors.
Methods: After a systematic review of the literature, the pooled prevalence of low-back pain in an unexposed population and the pooled odds ratio (OR) for each risk factor was calculated in a meta-analysis using a random effect model. An unbiased risk estimate for each risk factor was obtained by correcting the pooled OR for confounding by other risk factors. The probability of low-back pain was calculated with a logistic regression model. The input was (i) the age-dependent prevalence when not exposed and (ii) the unbiased risk estimates per risk factor of low and high exposure. The etiologic fraction was calculated to determine the level of work-relatedness.
Results: The pooled prevalence for low-back pain among unexposed subjects was 22%, 30%, and 34% for the <35-year, 35-to-45-year, and >45-year age categories, respectively. The pooled OR was 1.51 [95% confidence interval (95% CI) 1.31-1.74] for manual materials handling, 1.68 (95% CI 1.41-2.01) for frequent bending or twisting, 1.39 (95% CI 1.24-1.55) for whole-body vibration, and 1.30 (1.17-1.45) for job dissatisfaction. For high exposure to manual materials handling, frequent bending or twisting, and whole-body vibration, the pooled OR was 1.92, 1.93, and 1.63, respectively.
Conclusions: The model is the first that estimates the probability of work-relatedness for low-back pain for a given worker with low-back pain seen by a general practitioner or an occupational health physician.