Long-term effects of whole-body vibration: a critical survey of the literature.

The relevant literature on the long-term effects of whole-body vibration (wbv) was analyzed in order to obtain condensed information concerning a possibly higher health risk due to long-term exposure, the relationships between the quality of exposure (intensity, duration, frequency) and pathological effects, the significance of individual factors, conclusions for standard setting, and medical health care of workers exposed to wbv. Vibration exposure was characterized by measured values in one third of papers, whereas more than 30% of the publications selected did not contain any exposure data. Health data of about 43 000 workers exposed to wbv and 24 000 persons in control groups were reported. The results indicate an increased health risk of the spine and of the peripheral nervous system after intense long-term wbv. With a lower probability, the digestive system, the peripheral veins, the female reproductive organs, and the vestibular system were also affected. Long-term effects on other organs cannot be precluded. Wbv can worsen certain endogenous conditions. Specific diagnostic features of pathological changes induced by wbv with frequencies below 20 Hz do not exist. On average, the health risk increases with higher intensity or duration of exposure, however, quantitative exposure-effect relationships cannot be derived at present. Since wbv near the Exposure Limit of the International Standard IS 2631 is not completely safe, this survey provides arguments in favour of a lower limit. Contra-indications for professional exposure to wbv and further research needs are discussed.