Case-control study of lung cancer among workers at a uranium processing plant

The purpose of this case-control study was to investigate the relationship between exposure to radiation resulting from the inhalation of uranium dust and the dust of uranium-bearing compounds and death due to lung cancer. Cases and controls were chosen from a cohort of white male workers employed at one uranium processing plant during World War II. The 330 cases consisted of all lung cancer deaths occurring in the cohort between 1943 and 1973. Level of exposure to radiation and other potential workplace carcinogens was determined for each worker using process manuals, industrial hygiene reports, air monitoring data and individual work histories. Smoking status and information regarding medical variables was determined from employee medical records. Cumulative radiation lung dose among study population members ranged from 0 to 75 rads. Data were analyzed using Mantel-Haenszel stratified analysis and logistic regression. Relative risk was found to increase with increasing level of lung dose exposure even after controlling for age, smoking status and other workplace exposures, but only for those who were over the age of 44 when first exposed. A statistically significant excess in risk was found for men in this hire age group with a cumulative lung dose of 20 rads or more. The risk associated with the overall work environment was also investigated using a summary measure of total workplace exposure called chemical rank. A similar relationship existed between chemical rank and lung cancer to that found for cumulative lung dose and lung cancer