Thyroid function in a group of former workers from a nuclear weapons research and development facility

Objectives. The overall goal of this research was to investigate the relationship between exposures encountered while working at a Department of Energy nuclear weapons National Laboratory (LANL) and thyroid function in a sample of retired former workers.; Methods. The first phase of this work compared thyroid function in former workers from a nuclear weapons facility to that of participants in the Third National Health and Nutrition Examination Survey (NHANES III). Serum thyroid stimulating hormone (TSH) and thyroid medication use were combined to measure thyroid function. The second phase examined the association between workplace exposures, specifically radiation and solvents, and thyroid function. These exposures were characterized according to a cumulative exposure index based on reported frequency and duration of exposure. While a single measure was used to describe radiation exposure, solvents were classified as chlorinated, aromatic or "other." The association between these indices, controlling for demographic and work variables, and thyroid status was determined by means of regression analyses.; Results. The first set of analyses demonstrated that LANL former workers had an increased risk for abnormal TSH levels (> 4.5 mIU/L) and/or thyroid medication use as compared to the NHANES III sample. Of note was the finding that adjusted rates for the LANL group exceeded those of the NHANES III population, suggesting that occupational or environmental exposures may contribute to the risk for thyroid dysfunction. Further analyses showed an increased risk of abnormal TSH level (> 4.5 mlU/L) and/or thyroid medication use in male former workers who reported past chlorinated solvent exposure. Past radiation exposure was not significantly associated with thyroid dysfunction.; Conclusions. Extensive research has been done on cancer outcomes and all-cause health mortality and morbidity in radiation workers in the nuclear weapons and power generating industries in the U.S. and Europe. Relatively few have investigated the relationship between their workplace exposures and non-malignant thyroid dysfunction. Although radiation exposure was not a significant predictor of thyroid dysfunction, chlorinated solvents demonstrated a modest relationship. Causal relationships between thyroid dysfunction and occupational and environmental exposures should be further investigated to inform approaches for prevention of adverse thyroid outcomes.