Hypothyroidism among former workers of a nuclear weapons facility.

BACKGROUND

Ionizing radiation alters thyroid function, and workers at a nuclear weapons facility may be exposed to above environmental levels of radiation.

METHODS

Hypothyroid status was determined for 622 former workers of a nuclear weapons facility located in Texas, using a combination of measured thyroid stimulating hormone (TSH) levels and thyroid medication history, as part of an on-going health surveillance program. We classified 916 unique job titles into 35 job categories.

RESULTS

According to the most stringent TSH definition used in this study (0.3-3.0 IU/ml), 174 (28.0%) former workers were considered to be hypothyroid; of these 66 (41.8%) were females and 108 (23.3%) were males. In logistic regression analysis adjusted for age, gender, and smoking status, only having worked as a material handler (n = 18) exhibited an elevated risk of developing hypothyroidism compared to other jobs (OR 3.88, 95% CI 1.43-11.07). This is one of the jobs with suspected exposure to radiation. No excess risk of hypothyroidism was observed for any of the other job categories.

CONCLUSIONS

There is suggestive evidence that only material handlers at this nuclear weapons facility may have elevated risk of hypothyroidism; further evaluation of thyroid health in this population is warranted.