EFFECTS OF EXPOSURE TO EXTERNAL IONIZING-RADIATION ON CANCER MORTALITY IN NUCLEAR WORKERS MONITORED FOR RADIATION AT ROCKETDYNE ATOMICS INTERNATIONAL/

Background and Methods A retrospective cohort study was conducted to e stimate the effects of low-level exposure to external (penetrating) ra diation on cancer mortality among 4,563 workers monitored for external radiation between 1950 and 1993 at a nuclear research and production facility in Southern California.Results Of the 875 deaths that occurre d before 1995, 258 were due to cancer as the underlying cause. Externa l comparisons of male subjects with the U.S. white male population ind icated that the workers had lower rates of dying from all causes and a ll cancers, but a higher rate of dying from leukemia. Internal compari sons of workers exposed at different dose levels, using risk-set analy ses with adjustment for confounders, demonstrated an increased mortali ty rate in workers exposed to 200 mSv for hemato- and lymphopoietic ca ncers and for lung cancer. Mortality rates for total cancers and ''rad iosensitive'' solid cancers increased monotonically with cumulative ra diation dose, but no trends were observed for ''nonradiosensitive'' ca ncers. Conclusions Despite possible residual confounding and low preci sion for estimating effects on specific cancers, these findings indica te that chronic, low-level radiation exposure may have more generalize d carcinogenic effects than have been observed in most previous invest igations. Such effects may have become evident as a result of the rela tively long follow-up period in the present study. Am. J. Ind. Med. 35 :21-31, 1999. (C) 1999 Wiley-Liss, Inc.