[Review of dose-response relationship between low level vibration and lower back pain]

Whole-body vibration (WBV) with high level acceleration is found in the workplaces of construction and mining, and has been reported to be associated with low back pain (LBP) experienced by operators of heavy vehicles as an occupational health problem. Because the work conditions with exposure to WBV include bending and twisting of the low back and other factors, the causal relationship between WBV and LBP has not yet been affirmed. A review suggesting the dose-response relationship between WBV with low acceleration and LBP has been published, although there is little evidence supporting the causal relationship. Therefore, we reviewed the dose-response relationship between WBV with low acceleration and LBP.

We examined original articles which reported a dose-response relationship between WBV and LBP in addition to review articles with almost the same aims.

Studies which examined imaging findings such as CT and MRI, objective indicators of LBP, do not confirm the causal relationship. Although many studies demonstrated a positive relationship between working periods and incidence of LBP, there were very few reports which recognized a dose-response relationship for the vibration acceleration below 1.0 m/s(2) in which the 8-h energy-equivalent, combined frequency-weighted vibration of three diagonal, that is x, y and z, axes (root-sum-of-squares), Asum(8) was used as an index of vibration exposure.

This paper reject the hypothesis of a dose-response relationship between WBV with low acceleration and LBP, concluding there is no evidence linking low level exposure to WBV with LBP for the Japan Society for Occupational Health to recommend 0.35 m/s(2)/as of Asum(8) as a tentative occupational exposure limits for WBV.