EVALUATION OF INTERNAL ALPHA-PARTICLE RADIATION EXPOSURE AND SUBSEQUENT FERTILITY AMONG A COHORT OF WOMEN FORMERLY EMPLOYED IN THE RADIUM DIAL INDUSTRY

This study examined the effect of internal exposure to alpha-particle radiation on subsequent fertility among women employed in the radium d ial industry prior to 1930, when appreciable amounts of radium were of ten ingested through the practice of pointing the paint brush with the lips, The analysis was limited to women for whom a radium body burden measurement had been obtained and who were married prior to age 45 (n = 603). Internal radiation dose to the ovary was calculated based on initial intakes of radium-226 and radium-228, average ovarian mass, nu mber and energy of alpha particles emitted, fraction of energy absorbe d within the ovary, effective retention integrals and estimated photon irradiation. Time between marriage and pregnancy, number of pregnanci es and number of live births served as surrogates for fertility. Radia tion appeared to have no effect on fertility at estimated cumulative o varian dose equivalents below 5 Sv; above this dose, however, statisti cally significant declines in both number of pregnancies and live birt hs were observed. These trends persisted after multivariable adjustmen t for potential confounding variables and after exclusion of subjects contributing a potential classification or selection bias to the study . Additionally, the high-dose group experienced fewer live births than would have been expected based on population rates. There were no dif ferences in time to first pregnancy between high- and low-dose groups. These results are consistent with earlier studies of gamma-ray exposu res and suggest that exposure to high doses of radiation from internal ly deposited radium reduces fertility rather than inducing sterility. (C) 1997 by Radiation Research Society.