RESUMEN
We have examined 272 steelworkers, aged 45 to 55 years, by means of the ECSC-questionnaire and the following lung function tests: vital capacity (VC) and forced expiratory volume in one second (FEV1), residual volume (RV) and total lung capacity (TLC); maximal expiratory flow rates (Vmax, Vmax 50, Vmax 75); specific airways conductance (SGaw); slope of the N2 alveolar plateau after oxygen inhalation (delta N2) and the bolus closing volume (CV). The influence of smoking on respiratory symptoms and lung function was confirmed. In order to assess the influence of occupational pollution a sample of 163 workers was classified according to smoking habits and workplace (either LD-steelplant and continuous casting department, or sheet rolling mill). In the nonsmokers group we found that the workers from the steelplant and continuous casting department (n = 12) had a significantly lower SGaw value (delta = 0.065 cm H2O-1 . s-1, p less than 0.01) and a significantly higher CV value (delta = 4.5% VC, p less than 0.05) than the workers from the sheet rolling mill (n = 11). Differences in FEV1/VC, Vmax 50 and Vmax 75 were not significant, but were also consistent with a slight airflow obstruction in the steelplant workers. In the smokers (n = 99) and exsmokers (n = 41) groups no differences existed between both working categories. Our results suggest that nonsmoking workers from the steelplant and the continuous casting department have undergone moderate, but detectable effects from industrial pollution. These effects are probably masked by those of tobacco in smokers and exsmokers.
