The occurrence of low-back pain (LBP) was investigated in a population of 1155 tractor drivers exposed to whole-body vibration (WBV)and postural stress (response rate 91.2%), and in a control group of 220 office workers(response rate 92.2%). The subjects were questioned about several types of low-back sympton (LBP, sciatic pain, acute LBP, transient and chronic LBP) and various work- and individual-related risk factors, by using a standardized questionnaire. Vibration measurements were performed on a representative sample of the vehicles driven by the tractor drivers in the last ten years. Vibration magnitude and duration of exposure were used to calculate a vibration dose for each tractor driver. Perceived postural load was assessedin terms of frequency and/or duration of awkward postures at work. The prevalence of LBP was found to be greater in the tractor driversthan in the controls. After controlling for potential confounders bylogistic modelling, low-back disorders were found to be significantly associated with both vibration dose and postural load. Back accidents and age were also significant predictors for LBP. Quantitative regression analysis indicated that vibration exposure and postural load were independent contributors to the increased risk for LBP according to a multiplicative model
Abstract