An updated review of epidemiologic studies on the relationship between exposure to whole-body vibration and low back pain (1986-1997).

The aim of this study is to update the information on the epidemiologic evidence of the adverse health effects of whole-body vibration (WBV) on the spinal system by means of a review of the epidemiologic studies published between 1986 and 1997. In a systematic search, using several databases, of epidemiologic studies of low back pain (LBP) disorders and occupations with exposure to WBV, 45 articles were retrieved. The quality of each study was evaluated according to criteria concerning the assessment of vibration exposure, assessment of health effects, and methodology. The epidemiologic studies reaching an adequate score on each of the above-mentioned criteria were included in the final review. A meta-analysis was also conducted in order to combine the results of independent epidemiologic studies. After applying the selection criteria, 17 articles reporting the occurrence of LBP disorders in 22 WBV-exposed occupational groups reached a sufficient score. The study design was cross-sectional for 13 occupational groups, longitudinal for four groups and of case-control type for one group. Two studies included both cross-sectional and follow-up data on the occurrence of LBP disorders in four occupational groups. The main reasons for the exclusion of studies were insufficient quantitative information on WBV exposure and the lack of control groups. The findings of the selected studies and the results of the meta-analysis of both cross-sectional and cohort studies showed that occupational exposure to WBV is associated with an increased risk for LBP, sciatic pain, and degenerative changes in the spinal system, including lumbar intervertebral disc disorders. Owing to the cross-sectional design of the majority of the reviewed studies, this epidemiologic evidence is not sufficient to outline a clear exposure-response relationship between WBV exposure and LBP disorders. Comparing the epidemiologic studies included in this review with those conducted before 1986, it is concluded that research design and the quality of exposure and health effect data in the field of WBV have improved in the last decade.