Back disorders in crane operators exposed to whole-body vibration.

In The Netherlands so far little research has been carried out to investigate the health effects of exposure to whole-body vibration at work. In a retrospective (10-year) follow-up study, the incidence of permanent work disabilities in crane operators exposed to vibration was compared to that of a control group. The emphasis in this presentation is on disablement because of back disorders. Among the crane operators with more than 5 years of exposure to vibration, more disability due to back trouble occurred than in the control group. The incidence density ratio (IDR) exceeded 2 for disability because of degeneration of the intervertebral disc, after adjustment for age, nationality, shift work and calendar year. With increasing years of exposure, the risk ratio for disability because of intervertebral disc disorders also increased. The risk ratio for a disability pension due to disease of the intervertebral disc for crane operators with more than 5 years of exposure was almost 3 compared to the control group. A combination of exposure to whole-body vibration, an unfavorable posture, and climatic conditions is responsible for the development of these health effects.