A mortality study of North Carolina workers diagnosed with silicosis during 1940 through 1983 was conducted. Mortality rates from tuberculosis, cancer of the intestine and lung, pneumonia, bronchitis, emphysema, asthma, pneumoconiosis, and infectious kidney disease were significantly increased in white silicotics when compared to general population rates in the United States. Mortality rates from tuberculosis, ischemic heart disease, and pneumoconiosis were significantly increased in nonwhites. Lung cancer standardized mortality ratios (SMRs) were 2.3 in silicotics with no exposures to other known occupational carcinogens and 4.5 in silicotics who had other possible exposures such as asbestos product manufacturing, olivine mining, talc mining, insulation work, and foundries. Lung cancer mortality was increased in cigarette smokers. Lung cancer mortality was also increased in subjects diagnosed with silicosis while still employed in the dusty trades, even in those who had no exposures to other known occupational carcinogens. Lung cancer mortality was increased in cigarette smokers who had been diagnosed with silicosis after leaving employment and in smokers diagnosed while employed in the dusty trades. While the findings are consistent with an association between silicosis and lung cancer, the authors add the cautionary note that whether this increase in lung cancer is due to the silica (14808607) exposure is not proved by these data.
NIOSH-Author; Silica-dusts; Cancer-rates; Risk-factors; Mortality-surveys; Mineral-dusts; Lung-cancer; Humans; Epidemiology; Pneumoconiosis;
Author Keywords: silicosis; lung cancer; mining; construction trades; foundry workers; quarry exposures; asbestos products; coal workers' pneumoconiosis; tuberculosis; non-whites