Risk of thyroid nodules in subjects occupationally exposed to radiation: a cross sectional study.

Objectives: To examine, by ultrasonography the prevalence of thyroid nodules in a cross sectional study of male medical workers occupationally exposed to chi radiation at the Pisa hospital, in comparison with controls matched for age and sex.

Methods: 50 male medical workers exposed to radiation were randomly matched for age (+/- 2 years) with 100 male workers not occupationally exposed to ionising radiation who lived in a slightly iodine deficient area of Tuscany (Lunigiana) (control group 1), and with 100 male workers not exposed to radiation who lived in the same area (Pisa) (control group 2).

Results: Of the occupationally exposed subjects, thyroid nodules were detected in 19/50 (38.0%). Among controls, thyroid nodules were detected in 19/100 subjects of control group 1 and in 13/100 of control group 2. Comparison of exposed and control groups, stratified into 30-39, 40-49, and 50-59 year old age subgroups, showed a higher significant relative risk for thyroid nodules in the exposed subjects.

Conclusion: The results suggest that occupational exposure to radiation may be a risk factor for thyroid nodules.