BRONCHIAL RESPONSIVENESS IN ACTIVE STEELWORKERS

Coke-oven workers are exposed to dust and irritant gases, Therefore th ey are at risk of developing lung diseases including chronic bronchiti s. Nonspecific bronchial hyperresponsiveness (BHR has been advocated a s a potential risk factor predisposing to the development of chronic b ronchitis. In a previous study, we showed that prevalence of BHR was h igher in retired coke-oven workers than in retired blast furnace worke rs. The present study was carried out to determine the prevalence of B HR in active steelworkers. Thus, 137 coke-oven workers and 150 blast f urnace workers underwent clinical examination, a standardized question naire for the study of respiratory symptoms, pulmonary function testin g and methacholine aerosol challenge. The study demonstrates a higher prevalence and degree of BHR (provocative concentration of methacholin e causing a 20% fall in forced expiratory volume in one second (PC20) less than or equal to 8 mg.mL(-1)) in coke-oven workers than in blast furnace workers (31.4 versus 6.7%; p<0.001). Moreover, the frequency o f respiratory symptoms and basal bronchial obstruction were greater am ong coke-oven workers with BHR in nonresponders, The basal maximum exp iratory flow from 25-75% of forced vital capacity and the respiratory symptoms were correlated with bronchial responsiveness. The lock of co rrelation observed between BHR and the intensity of smoking or years s pent in coke-oven environment may be explained by the high proportion of smokers, the worker turnover in the steel plant, and the ''healthy worker effect''. In conclusion, the higher prevalence and degree of br onchial hyperresponsiveness in coke-oven workers suggests that coke-ov en pollutants are more intense irritants than those that escape from b last furnaces.