Prevalence of Thyroid Diseases in an Occupationally Radiation Exposed Group: A Cross-Sectional Study in a University Hospital of Southern Italy.

BACKGROUND

Thyroid diseases occur more frequently in people exposed to ionizing radiation, but the relationship between occupational exposure to ionizing radiation and thyroid pathologies still remains unclear.

OBJECTIVE

To evaluate the prevalence of thyroid diseases in healthcare workers exposed to low-level ionizing radiation compared with a control group working at the University Hospital of Bari, Southern Italy, and living in the same geographical area, characterized by mild iodine deficiency.

METHODS

We ran a cross-sectional study to investigate whether healthcare workers exposed to ionizing radiation had a higher prevalence of thyroid diseases. Four hundred and forty-four exposed healthcare workers (241 more exposed, or "A Category", and 203 less exposed, or "B Category") and 614 nonexposed healthcare workers were enrolled during a routine examination at the Occupational Health Unit. They were asked to fill in an anamnestic questionnaire and undergo a physical examination, serum determination of fT3, fT4 and TSH, anti-TPO ab and anti-TG ab and ultrasound neck scan. Thyroid nodules were submitted to fine needle aspiration biopsy when indicated.

RESULTS

The prevalence of thyroid diseases was statistically higher in the exposed workers compared to controls (40% vs 29%, adPR 1.65; IC95% 1.34-2.07). In particular, the thyroid nodularity prevalence in the exposed group was approximately twice as high as that in the controls (29% vs 13%; adPR 2.83; IC95% 2.12-3.8). No statistically significant association was found between exposure to ionizing radiation and other thyroid diseases.

CONCLUSION

In our study, mild ionizing radiation-exposed healthcare workers had a statistically higher prevalence of thyroid diseases than the control group. The results are likely due to a closer and more meticulous health surveillance programme carried out in the ionising radiation-exposed workers, allowing them to identify thyroid alterations earlier than non-exposed health staff.