Dose-Response Relationships for Female Radium Dial Workers

Abstract

Among 1474 women employed in the United States radium dial-painting industry before 1930, there are 61 known cases of bone sarcoma and 21 cases of carcinoma of the paranasal sinuses or the mastoid air cells (''head carcinomas''). The relative effectiveness of /sup 226/Ra and /sup 228/Ra and dose-incidence relationships were examined for the 759 of these women whose radium body burden has been determined; there are 38 cases of bone sarcoma and 17 cases of head carcinoma in this group. Incidence (I) was expressed as tumor cases per person-year and the dose parameter (D) was the quantity (microcuries) of radium that entered the blood during the period of exposure. To the observed data for each type of tumor were fitted equations that can be formulated from the general form I = (C + alpha dD+ ..beta..D/sup 2/)e-..gamma../sup D/, where C, the natural incidence for this population, was about 10-/sup 5/ per person-year. For each equation, the best values of the dose coefficients were found by a least-squares fitting procedure. An equation of the form I = (C + BD/sup 2/)e-/sup ..gamma..D/ provided the best fit for the bone sarcomas, when the dose was expressed as microcuries of /sup 226/Ra plusmore » 2.5 times microcuries of /sup 228/Ra. An acceptable fit to the head carcinoma data was provided by the linear equation I = C + d alpha ..gamma.. with D equal to microcuries of /sup 226/Ra. As a test of bias due to selection of cases with known symptoms of malignancy, the analyses were repeated after removal of all cases for whom radium was determined only after exhumation, and no significant changes in the fitted coefficients were found. The dose-incidence equations obtained when the dose was expressed as average skeletal dose in rad are also given.« less