PURPOSE: Our study tries to estimate the influence of smoking on serum levels of thyroid hormones, antithyroid peroxidase and antithyroglobulin antibodies among women with various clinical forms of chronic autoimmune thyroiditis.
METHODS: Case report study included 310 inpatients with chronic autoimmune thyroiditis, hospitalised in the Endocrinology Department of Clinical Emergency Constanta County Hospital, from January 2006 to December 2009. The cases were categorized as smokers or nonsmokers. For each woman, a standardized questionnaire, including questions about smoking habits, alcohol intake, menopausal status, and hormonal treatments (estrogen especially) or other medications was applied. Smoking habits were categorized in the following way: nonsmokers (women who had never smoked or former smokers who smoked less than 10 pack-per-year), one-pack-per-day smokers (group I), two-packs-per-day smokers (group II) and smokers of more than two packs per day (group III). Thyroid function was evaluated by measurements of serum thyrotropin, free thyroxine, triiodothyronine, antithyroidperoxidase and antithyroglobulin antibodies.
RESULTS: In our study group, 24% (n=75) of patients were smokers. Smoking in women was highly reported in 69% of smokers (n=52/75). Female smokers were almost 10 years younger than males (mean aged 41.25 ± 7.81 yrs vs 50.60 ± 9.44 yrs). Serum levels of antithyroid peroxidase antibodies were significantly increased (p < 0.001) in smokers patients, compared with the nonsmokers patients. Most of the cases with chronical autoimmune thyroiditis associated with hypothyroidism were diagnosed in female smokers (n= 41/53; 77%). Subclinical chronical autoimmune thyroiditis associated with smoking in women (n=8) had higher serum thyrotropin and lower free thyroxine concentrations. Serum levels of antithyroglobulin antibodies were significantly increased (p < 0.01) in smokers vs nonsmokers.
CONCLUSIONS: Smoking increases the serum levels of antithyroid antibodies in womens with chronic autoimmune thyroiditis.
CLINICAL IMPLICATIONS: One component of tobacco smoke is cyanide, which is converted to thiocyanate, which acts as an anti-thyroid agent, directly inhibiting iodide uptake and hormone synthesis. Smoking status should be considered in the evaluation of patients in whom hypothyroidism and or autoimmune thyroiditis is suspected.
DISCLOSURE: The following authors have nothing to disclose: Oana Arghir, Ioana Buzoianu, Elena Dantes, Paraschiva Postolache, Mihaela Trenchea, Eduard Circ
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