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

¹ Coronel Institute for Occupational Health, Netherlands

^* To whom correspondence should be addressed. E-mail: i.j.tiemessen{at}amc.uva.nl.

Accepted 9 January 2008

	Abstract

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: We assessed individual factors, work-related risk factors, various LBP outcome measures (12-month LBP, driving-related LBP, LBP intensity [Von Korff pain scale¡ 5] and LBP disability [Roland Morris disability scale ¡ 12]) 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 two points in time: T0 and one-year follow-up (T1). Data were collected using a self-administered questionnaire and actual field measurements according to the 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: A sample of 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, we 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), rooth 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: We 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.

Keywords: Dose-response pattern, Low back pain, Whole body vibration