Increased primary autoimmune thyroid diseases and thyroid antibodies in sarcoidosis: evidence for an under-recognised extrathoracic involvement in sarcoidosis?

OBJECTIVE AND DESIGN Sarcoidosis has been associated with thyroid diseases. However, until today no definite conclusions have been drawn. We aimed to assess the frequency of thyroid disorders and the levels of thyroid hormones and thyroid antibodies in 68 sarcoidosis patients and 75 controls. Additionally, we performed ultrasonography and fine-needle aspiration. RESULTS In this prospective case control study conducted in the University Hospital of Larissa, Greece, overt thyroid disease was present in 29.4% of patients and 16.1% of patients presented clinical autoimmune thyroid disease. Sarcoidosis patients had a significantly higher frequency of serological autoimmunity. Female patients had significantly increased frequency of positive TSH receptor antibodies (TRAbs) and antithyroid peroxidase antibodies (TPOAbs) when compared to gender-matched controls (40% vs 0%, p<0.001, and 28.8% vs 11.86%, p=0.029, respectively). The hypoechoic pattern of the thyroid was more frequent in female patients vs controls (p<0.001). Male patients had a higher frequency of TRAbs and hypoechoic pattern of the thyroid gland (43.4% vs 0%, p=0.002, and 39.1% vs 6.25%, p=0.021, respectively). Indices of thyroid autoimmune disease were significantly more frequent in sarcoidosis patients vs gender-matched controls. Increased TPOAbs were significantly associated with clinical autoimmune disease in sarcoidosis. CONCLUSIONS Overall, the findings derived from this study suggest that thyroid disorders are frequent in sarcoidosis. This association may potentially be the result of increased thyroid antibodies.