Epidemiological study of cancer mortality among workers exposed to occupational low levels of ionizing radiation

A case-control study nested in a cohort was conducted to investigate the relationship between cancer mortality and occupational exposures among the male employees of one of the Department of Energy facilities. 423 cancer cases and 846 matched controls were identified from the cohort of workers employed in the period 1943-1977. All deaths attributable to cancer were identified as cases. Detailed annual dose measurements of external radiation exposure were available for all the study members, and were assessed for completeness and accuracy. Internal radiation hazard codes were assigned. Detailed work history information was obtained. The overall risk estimates for the study population may follow the conservative extrapolated models. The application of various models to the observed data revealed the shortcoming of making a clear distinction as to the dose-response function most appropriate to the observed data in the low dose region. Despite the uncertainties a suggested increase in cancer mortality risk with increasing radiation dose has been demonstrated. The predicted trend is best fitted with a linear quadratic, quadratic or linear model