SISTER-CHROMATID EXCHANGE ANALYSIS IN WORKERS EXPOSED TO NOISE AND VIBRATION

Workers chronically exposed to whole-body vibration and noise are know n to develop pathophysiological and psychological disturbances. The fr equencies of sister chromatid exchanges (SCEs) and of cells with high frequencies of SCEs (HFCs) were analyzed in lymphocytes of 50 workers occupationally exposed to vibration and noise and of 34 controls. The exposed group included: individuals operating hand-vibrating tools (gr oup I), 'test-cell operators' (group 2) and 'run-up' operators (group 3) from an air base and helicopter pilots (group 4). The statistical a nalysis of the mean SCE count per cell was carried out by multiple reg ression analysis, comparing various predictor variables: exposure grou p, duration of exposure, age and cigarette consumption. Only cigarette consumption and exposure group were found to be significantly correla ted with the mean SCE frequency. After allowing for the effects of smo king, the analysis indicates that: (1) there was no significant differ ence between group 1 and controls (p > 0.05); (2) the differences betw een group 2 and group 0, group 3 and group 0 and group 4 and group 0 w ere all highly significant (p < 0.001); (3) there was no significant d ifference between groups 2 and 3 (p > 0.05), nor between groups 2 and 3 combined and group 4 (p > 0.05); (3) exposure groups 2, 3 and 4 comb ined, had a significantly elevated mean SCE frequency compared to the control group (p < 0.0001). Statistical analysis of the proportion of HFCs was consistent with these results. Our data suggest that chronic exposure to whole-body vibration and noise may lead to an increase in the level of SCEs in man. The observed effects may not reflect a direc t action of these physical agents on DNA. Alternative explanations may include some of the whole-body vibration and noise-induced or stress- induced pathophysiological alterations which may indirectly induce SCE formation.