The relationship between occupational radiation exposure and thyroid nodules

Considering that thyroid nodules and thyroid cancer occur more frequently in people exposed chronically to radiation, the aim of this study was to evaluate the prevalence of thyroid nodules in a population occupationally exposed to radiation, in the hospitals of Isfahan. In this case control study the prevalence of thyroid nodules in radiation exposed workers was determined by ultrasonography which was performed by a radiologist. The results were compared with the results of another study among the adult population of Isfahan city which were selected by Cluster – random sampling method. The two studied groups were matched according to sex and age. The studied population in case and control groups was 124 and 471 respectively. The prevalence of thyroid nodule in the case and control groups was 22.6% and 24.6% respectively (p > 0.05). Thyroid nodule was more prevalent in females in the control group but there was no difference between the females and males of the case group (p > 0.05).The number of thyroid nodules (single or multiple) and calcification were not different for the two groups (p > 0.05). Moreover, the echo pattern of thyroid nodules for hypoechogenicity was not different in the two groups (p > 0.05). In our study, there was no correlation between occupational chronic exposure to a low dose of radiation and the risk of developing thyroid nodules. Further studies with a larger sample size and the consideration of different doses of radiation, in accordance with the iodine status and thyroid function are necessary.