Risk assessment of vascular disorders by a supplementary hand–arm vascular weighting of hand-transmitted vibration

Purpose To provide an updated epidemiological validation for a supplementary method for assessing the risk of vascular disorders from hand-transmitted vibration. Methods The occurrence of vibration-induced white finger (VWF) in the vibration-exposed workers of the Italian cohort of the EU VIBRISKS study was related to measures of daily vibration exposure expressed in terms of r.m.s. acceleration magnitude normalised to an 8-h day, frequency weighted according to either the frequency weighting W h defined in international standard ISO 5349-1:2001 [ A h (8) in ms − 2 ] or the hand–arm vascular frequency weighting W p proposed in the ISO technical report (TR) 18570:2017 [ A p (8) in ms − 2 ]. To estimate a threshold value for vascular hand–arm vibration risk, the W p -weighted vibration exposure value E p,d (in ms − 1.5 ) was calculated according to the ISO/TR document. The difference in the predictions of VWF between the exposure measures calculated with the frequency weightings W h or W p was investigated by means of logistic modelling. Results Measures of daily vibration exposure constructed with the frequency weighting W p [ A p (8) and E p,d ], which gives more importance to intermediate- and high-frequency vibration, were better predictors of the occurrence of VWF in the vibration-exposed workers than the metric derived from the conventional ISO frequency weighting W h [ A h (8)]. There was some epidemiological evidence for a threshold value of E p,d for the onset of VWF in the vibration-exposed workers. Conclusions Measures of daily vibration exposure evaluated with the vascular weighting W p performed better for the predictions of VWF than those obtained with the frequency weighting W h recommended in ISO 5349-1.