Epidemiological and clinical studies of polyvinylchloride workers

We have reported previously a medical survey of 818 present and past workers at a factory making polyvinylchloride (PVC) in which we showed that exposure to fine PVC dust was associated with a slight average reduction in the results of tests of breathing capacity, and with the presence of small spots visible in X-rays of the lungs.The present studies were designed to identify any chest illness in men who had worked in dustier plants in the factory but who had not been seen in the previous survey, and to examine similarly men working at a second factory manufacturing PVC; to re-examine the relationship between PVC dust exposure and small spots in the chest X-ray since in the first study there had been some disagreement between expert readers over the interpretation of the X-ray appearances, and to discover how seriously men may have been affected by PVC dust.Two hundred and twenty-nine additional men were seen at the first factory, and little chest illness was found among them. One hundred and twenty-seven men were seen at the second factory, and even less illness was found in this workforce. Each man was sent a brief confidential medical report.The X-rays were re-read by the same three experienced readers whose results were reported previously, and also by another panel of five readers. The readings confirmed the results of our earlier study, in that PVC dust exposure was found to be associated with the presence of small spots in the chest X-ray. Again, only some readers detected the effect of PVC dust, and the reasons for these differences probably include the slight degree of the abnormalities, which cannot be distinguished in an individual X-ray from changes related to age.These changes of the chest X-ray were slight, on the borderline between normality and abnormality, and clinical examinations of a group of men who had these spots indicated that the health of their lungs was no worse than that of a group of men of similar age and smoking habits who had normal chest X-rays (except for a slight increase in sputum). We conclude that the presence of these spots does not indicate that PVC dust has seriously affected the lungs. Some men who had experienced relatively high estimated dust exposures were also examined if their breathing tests results were lower than those of other men. The non-smokers selected in this way all had healthy lungs, but some of the smokers had serious reductions’ of their breathing tests results. This was probably the result of their smoking habit, and there was no evidence to suggest that PVC dust had seriously damaged their lungs.We conclude that exposure to PVC dust has been shown to cause a slight reduction of the results of tests of breathing and slight abnormalities of the chest X-ray, but that there is no evidence that PVC dust has caused serious illness among the workforce, although the possibility of a rare idiosyncratic response to the dust cannot be excluded.