Cioffi DL, Fontana L, Leso V, et al. - In this study, the possible role of occupational low dose ionizing radiation exposure was explored in increasing the healthcare workers’ risk of thyroid functional alterations. Researchers compared 120 healthcare workers exposed to ionizing radiation (60 belonging to category A with a potential exposure to an annual dose between 6 and 20 mSv and 60 to category B potentially exposed to an annual dose between 1 and 6 mSv) with a control group consisting of 60 unexposed healthcare subjects assessing serum levels of different thyroid function parameters as free triiodothyronine, free thyroxine, thyroid-stimulating hormone, and thyroid autoantibodies. This study examined age, gender, history of thyroid diseases, job task, dosimetric values as possible influencing factors using linear and multiple logistic regression analysis. This study's findings demonstrate that low dose ionizing radiation exposure would seem to significantly affect levels of free triiodothyronine, free thyroxine, thyroid-stimulating hormone, then implying a possible elevated risk of hypothyroidism in healthcare workers although no association could be ascertained with exposure category. Nevertheless, further studies are required to verify such a relationship on a greater number of workers in order also to define a possible dose-response relationship.