Asbestos exposure, pleural plaques and the risk of lung cancer.

Studies which have evaluated the relationship between pleural plaques and smoking have found a higher prevalence of smokers among persons with pleural plaques. Pleural plaques are a relatively frequent finding among persons with occupational exposure to asbestos. Some studies, but not others, have shown that persons with pleural plaques have a higher risk of lung cancer. None of these studies controlled for the effects of smoking, and since smoking is more prevalent among persons with pleural plaques, it is unlikely that the increased risk of lung cancer to persons with pleural plaques, found in some studies, is due to the pleural plaques.