ABSTRACT

Although it has been studied for many decades, it is fair to say that occupational exposure to vibration is still one of the least understood among the physical risk factors. There are three main reasons why this is the case: a) the identification of a simple yet effective descriptor of exposure (the conceptual analogue to LEX for noise) has turned out to be quite complicated because of the presence of many co-factors (e.g. body mass and body mass index for whole-body vibration, grip force, push force for hand-transmitted vibration) along with the two core elements ‘intensity of vibration’ and duration of exposure; b) apart from the well-known, but admittedly rare Raynaud syndrome (also known as ‘white finger syndrome’), exposure to vibration is often ill-correlated with pathological effects. Both objective factors (e.g. posture) and individual susceptibility play a large role, and the resulting dose-effect relationship is quite vague; c) while the cochlea usually can be assumed to be the only target in the case of exposure to noise, there are several possible targets for exposure to vibration, which can be categorised as belonging to the muscle-skeletal system, the neurological system or the vascular system. Data about individual effects have been insufficient to determine individual dose-effect relationships. The single relationship established in the standard, which was meant to be applied to all effects, is clearly inadequate to provide a good picture for any of them individually. Most work has traditionally focused on damage to the vascular system, so presumably this is the effect that the standards are most fitted to deal with.