Platelet function and clotting parameters of vibration-exposed foundry workers.

Platelet aggregation and blood clotting parameters were studied in 22 workers (84 %) using pneumatic riveting and grinding hand tools and in 20 workers (90 %) not exposed to vibration but comparable with respect to age, anthropometric data, smoking and drinking habits, and atherogenic risk factors. The weighted acceleration levels of the vibrating tools are reported. According to Taylor's grading system for vibration-induced white fingers, 15 exposed workers (57 %) were in stage OT, 9 (34 %) in stage 0N, and 1 (4 %) in stage 1. Between the reference and the vibration-exposed groups no differences in the platelet aggregation indices both "in vitro" (adenosine-diphosphate, epinephrine, threshold adenosine-diphosphate concentration) and "in vivo" (platelet factor four, beta-thromboglobulin) were found. In addition the clotting parameters (prothrombin index, activated partial thromboplastin time, fibrinogen, antithrombin III) and the immunoglobulins G, A, and M were normal in the two groups. The measurement of skin temperature of the third right finger before and after the cold provocation test showed that the vibration exposed workers experienced a stronger vasoconstriction of the digital vessels than the referents. It is concluded that, in the early stages of vasospastic disorders, segmental vibration can induce peripheral vascular hyperreactivity without changes in the platelet function and clotting parameters.