Low back pain in drivers exposed to whole body vibration: analysis of a dose-response pattern

Objective: Analysis of a dose-response pattern between exposure to whole body vibration (WBV) and low back pain (LBP) in a group of drivers. Methods: This study assessed individual factors, work-related risk factors, various LBP outcome measures and LBP disability in a group of drivers (n = 571) approached at baseline (T0), as well as the WBV magnitude of a representative sample of their vehicles (n = 49), at T0 and at 1-year follow-up (T1). Data were collected using a self-administered questionnaire and actual field measurements according to ISO 2631-1. The magnitude and duration of vibration exposure and a variety of daily and cumulative WBV-exposure measures were calculated for each driver. Results: 229 drivers (40.1%) completed both questionnaires (T0 and T1). The magnitude of WBV was comparable over time. Depending on the LBP outcome, various individual factors ( marital status, back trauma and smoking) and work-related risk factors (previous job with heavy physical loading, lifting, bending and the physical risk index) related significantly to onset (all, p < 0.05). After adjusting for these contributing factors, the study found a significant trend (an increase in odds ratios of developing LBP with an increase in WBV exposure) for driving-related LBP with daily driving time (p < 0.03), and the cumulative measures total hours of exposure (p < 0.01), root sum of squares at total dose (p, 0.05) and root sum of quads at total dose (p, 0.01). No significant trend was found for 12-month LBP. No analysis on a possible dose-response pattern could be derived for either LBP intensity or LBP disability, due to low prevalence. Conclusion: The investigation found a dose-response pattern between WBV exposure and driving-related LBP. No indication of a dose-response pattern was found between WBV exposure and 12-month LBP. Although this dose-response pattern is only an indication, these findings imply that WBV exposure might contribute to the onset of driving-related LBP.