Effects of cigarette smoking on pulmonary function in asymptomatic asbestos workers with normal chest radiograms

A comprehensive health screening program consisting of standardized health and occupational history questionnaire, blood chemistry profile, complete blood count, urinalysis, chest radiograph, and pulmonary function testing was organized for the Asbestos Workers Union Local Number 1 in St. Louis, Missouri. The program was available on a voluntary basis to all the workers in the Union. One hundred and thirty-five male caucasian workers or 44% of the membership volunteered to participate and all the data were used in this study. All blood chemistry profiles and urinalysis results were within normal limits. Twenty-two of the asbestos workers had radiologic pulmonary abnormalities as well as severe pulmonary function impairment. The remaining 113 workers were divided into subgroups based on the number of years of exposure to asbestos and their smoking history. Although asymptomatic, workers with more than 20 years exposure to asbestos had significantly decreased pulmonary functions compared to those with less than 20 years exposure. When smokers and nonsmokers were compared, an additive effect between smoking and asbestosis was observed. This study also discovered that significant decreases in pulmonary functions occur early in the exposure to asbestos.