CHEST RADIOGRAPHY IN PORTLAND-CEMENT WORKERS

To investigate the prevalence of pneumoconiosis in Portland cement wor kers, a controlled cross-sectional survey wets conducted. Chest radiog raphs of approximately 2640 Portland cement workers showed prevalence rates of about 1% for rounded and for irregular small opacities and ab out 2% for pleural abnormalities. After age and smoking adjustment, th e overall prevalences were still significantly elevated over controls, but when examined separately by smoking status, the significant incre ases were confined to smokers. Although statistically significant, the prevalences were only elevated about 1% in cement workers, compared W ith controls. A statistically significant relationship with exposure w as found for pleural abnormalities but not for rounded or irregular sm all opacities. Thus a weak association. exists between pulmonary radio graphic abnormalities and employment in US Portland cement plants, and there appears to be a dose-response relationship, between exposure an d pleural abnormalities.