Smoking and the Thyroid

Smoking is associated with a goitrogenic effect, especially in iodine-deficient areas, although it might have a protective effect against thyroid cancer. Smoking is associated with a higher risk of relapse of hyperthyroidism due to Graves’ disease. In addition, in Graves’ patients it poses a much higher risk of developing Graves’ orbitopathy, particularly in its severe forms, and of a lower/delayed response to immunosuppressive treatments for this extrathyroidal manifestation of Graves’ disease. At variance, smoking may have a protective effect on the development of chronic autoimmune thyroiditis and related hypothyroidism.