Irregular opacities in the lung, occupational asthma, and airways dysfunction in aluminum workers

We examined chest X-rays, measured expiratory flows and FVC by spirometry and TLC by projected lung area, ascertained respiratory data by questionnaires, and performed chest examinations in 670 Southeastern aluminum workers and 659 unexposed regional controls. Both groups were asbestos exposed. More aluminum workers had irregular opacities and fewer had pleural abnormalities than did regional pipefitter referents. The pulmonary function tests were expressed as percentage of predicted to adjust for height, age and duration of smoking based on a randomly selected U.S. reference population. Data from aluminum workers were compared to regional controls with students "t" tests run for unequal size groups. Aluminum workers had significant reductions in FEV1 of 3.2% predicted (p less than .003), FEF25-75 of 11.3% predicted (p less than .0001), FEF75-85 of 22.5% predicted (p less than .0001), and an increased TLC of 2.0% predicted (p less than .005). The 145 who had never smoked (NS) were compared with 124 NS controls and showed this same pattern of differences; but in smokers, the differences were significant for mid and terminal flows, but not for FEV1. In aluminum workers who never smoked, asthma prevalence by history was 7.6% vs. 4.0% in controls, and wheezes were heard in 21.4% vs. 2.4% in controls. In aluminum workers who were current smokers, asthma prevalence was 16.4% vs. 9.4% in controls, and wheezes were heard in 43.7% vs. 21.1% in controls. Aluminum workers had significantly more asthma, wheezing, airways obstruction, and pulmonary parenchymal abnormalities similar to asbestosis than did regional blue collar controls not melting and casting aluminum.