Radiation exposure and cancer mortality in uranium processing workers

Data from the Comprehensive Epidemiology Data Resource (CEDR) allowed me to study patterns of cancer mortality in a cohort of 4,014 uranium-processing workers. Employing risk-set analysis for cohort data, I estimated the effe cts of external (gamma) and internal (alpha) radiation on cancer mortality. My results indicate that Fernald workers exposed to ionizing radiation exp erienced an increase in mortality from total cancer (per 100 mSv external d ose rate ratio (RR) = 1.92; 95% confidence interval (CI) = 1.11-3.32), radi osensitive solid cancer (RR = 2.00; 95% CI = 1.02-3.94), and lung cancer (R R = 2.77; 95% CI = 1.29-5.95). Effects were strongest when exposure had occ urred at older ages (>40 years). In addition, I observed an increase in lun g-cancer mortality for workers exposed to greater than or equal to 200 mSv of internal (alpha) radiation (RR = 1.92; 95% CI = 0.53-6.96). Furthermore, my results demonstrate the importance of a long follow-up time when studyi ng solid cancers, the potential for bias due to worker selection associated with concomitant chemical exposures, problems of exposure measurement, con founding, and effect modification due to age at exposure. Owing to lack of data, a previous pooled analysis of uranium-processing workers could only p artially address these issues.