As someone who became hypothyroid (or at least, more so) after I stopped smoking, papers discussing these things are always of interest. Afraid I missed this when it was published, but better late than not at all.
Influence of cigarette smoking on thyroid gland – an update
Wpływ palenia papierosów na tarczycę – aktualizacja
Nadia Sawicka-Gutaj1, Paweł Gutaj2, Jerzy Sowiński1, Ewa Wender-Ożegowska2, Agata Czarnywojtek1, Jacek Brązert2, Marek Ruchała1
1Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poland
2Department of Obstetrics and Women’s Diseases, Poznan University of Medical Sciences, Poland
Nadia Sawicka-Gutaj M.D., Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Przybyszewskiego St. 49, 60–355 Poznań, Poland, tel.: +48 61 869 13 30 +48 61 869 13 30, fax: +48 61 869 16 82, e-mail: firstname.lastname@example.org
Many studies have shown that cigarette smoking exerts multiple effects on the thyroid gland. Smoking seems to induce changes in thyroid function tests, like decrease in TSH and increase in thyroid hormones. However, these alterations are usually mild. In addition, tobacco smoking may also play a role in thyroid autoimmunity. Many studies have confirmed a significant influence of smoking on Graves’ hyperthyroidism and particularly on Graves’ orbitopathy. Here, smoking may increase the risk of disease development, may reduce the effectiveness of treatment, and eventually induce relapse. The role of smoking in Hashimoto’s thyroiditis is not as well established as in Graves’ disease. Nonetheless, lower prevalence of thyroglobulin antibodies, thyroperoxidase antibiodies and hypothyroidism were found in smokers. These findings contrast with a study that reported increased risk of hypothyroidism in smokers with Hashimoto’s thyroiditis. Moreover, cigarette smoking increases the incidence of multinodular goitre, especially in iodine-deficient areas. Some studies have examined cigarette smoking in relation to the risk of thyroid cancer. Interestingly, many of them have shown that smoking may reduce the risk of differentiated thyroid cancer. Furthermore, both active and passive smoking during pregnancy might modify maternal and foetal thyroid function.
This review evaluates the current data concerning the influence of cigarette smoking on thyroid gland, including hormonal changes, autoimmunity and selected diseases. These findings, however, in our opinion, should be carefully evaluated and some of them are not totally evidence-based. Further studies are required to explain the effects of smoking upon thyroid pathophysiology. (Endokrynol Pol 2014; 65 (1): 54–62)
Key words: thyroid; smoking; tobacco; nicotine; thyroid hormones; TSH; TSH receptor autoantibodies; Graves’ disease; Hashimoto’s thyroiditis; postpartum thyroiditis