SILICOSIS AND LUNG-CANCER AMONG WORKERS IN NORTH-CAROLINA DUSTY TRADES

In 1940-1983, 760 cases of silicosis were identified among male North Carolina (NC) workers in dusty trades. Vital status was ascertained th rough 1983 for 714 silicotics, and death certificates were obtained fo r 546 of the 550 decedents. The standardized mortality ratio (SMR) for lung cancer based on United Stares rates was 2.6 [95% confidence inte rval (95% CI) 1.8-3.6] for whites, 2.3 (95% CI 1.5-3.4) for whites une xposed to other known occupational carcinogens, and 2.4 (95% CI 1.5-3. 6) for whites with no other exposure and diagnosed with silicosis whil e still employed in dusty trades. In addition, the age- and smoking-ad justed rate for silicotics was 3.9 times higher (95% CI 2.4-6.4) than that of nonsilicotic metal miners. This analysis effectively controlle d for confounding by age, cigarette smoking, exposure to other occupat ional carcinogens, and detection bias. The results congrue with the hy pothesis of an association between silicosis and lung cancer.