Background: The association of sarcoidosis (S) and thyroid autoimmunity has been reported by several studies in a wide range of variability. The aim of our study was to evaluate the prevalence of clinical and subclinical thyroid disorders in patients with S vs gender-matched and age-matched control subjects.

Methods: Thyroid hormones and antithyroid antibodies, thyroid ultrasonography and fine-needle aspiration were performed in 111 patients with S who had been consecutively referred to the Respiratory Pathophysiology Section of the University of Pisa, and the results were compared to 333 gender-matched and age-matched control subjects from the same geographic area.

Results: The odds ratio for subclinical hypothyroidism for female patients with S vs control subjects was 2.7 (95% confidence interval [CI], 1.3 to 5.9); for anti-thyroid peroxidase antibody titer (AbTPO) positivity, 2.2 (95% CI, 1.2 to 3.9); and for thyroid autoimmunity, 1.9 (95% CI, 1.1 to 3.2). The mean values of thyroid-stimulating hormone and AbTPO were higher in female S patients than in control subjects (p < 0.01). A significantly higher prevalence of clinical hypothyroidism (four patients) and Graves disease (three patients) was observed in female S patients than in control subjects (none; p = 0.005 and 0.0026, respectively). Two cases of papillary thyroid cancer were detected in S patients. No significant difference between S patients and control subjects was detected for free triiodothyronine and thyroxine, antithyroglobulin autoantibodies, thyroid volume and nodularity, and subclinical hyperthyroidism.

Conclusions: Thyroid function, AbTPO antibodies, and ultrasonography should be tested as part of the clinical profile in female S patients. Subjects who are at high risk (female subjects, those with positive AbTPOs, and those with hypoechoic and small thyroid) should have thyroid function follow-up and appropriate treatment in due course.