Cotton dust and smoking effects on lung function in cotton textile workers.

Both smoking and exposure to cotton textile dust have been associated with the development of chronic obstructive lung disease. The relative importance of these two effects are examined in this paper. This investigation is based on a cross-sectional study of white active and retire cotton textile workers 45 years and older seen in 1973 in Columbia, South Carolina with an average of 35 years worked in the mills. A questionnaire was completed and an expiratory flow volume curve obtained for each worker studied. Standard pulmonary function parameters including the forced vital capacity (FVC), the forced expired volume in one second (FEV1), and the maximum expiratory flow at 50% (MEF50%), and at 25% (MEF25%) were recorded. White residents 45 years and older from three communities studied from 1972 to 1974 were used as controls. A two-way analysis of variance examined both the effects of cotton dust and smoking on lung function. Both exposures significantly influenced lung function and were found to be additive and often equally important. When one effect was more important than the other, it was in FVC and FEV1 for cotton dust and in MEF50% and MEF25% for smoking.