Cigarette Smoking and the Thyroid

Abstract

Relevant English language articles published from 1970 through 1993 regarding the possible influence of cigarette smoking on the thyroid were identified through a MEDLINE search and manual searches of identified articles. Thiocyanate in tobacco smoke influences the thyroid by a competitive inhibition of iodine uptake and organification in the gland. Also the stimulation of the sympathetic nervous system by cigarette smoke and benzpyrene, another constituent of tobacco, is thought to influence thyroid gland function. The thyroid hormones and TSH receptor autoantibodies are not affected by smoking, but serum TSH levels have been found to be slightly reduced. Smokers have a higher frequency of goiter and increased serum thyroglobulin levels, especially in iodine-deficient areas. Graves' ophthalmopathy is strongly associated with cigarette smoking; the more severe the eye disease the stronger the association. Graves' disease without ophthalmopathy is also associated with smoking, though this association is weaker. Thiocyanate level in cord blood equilibrates completely with the level in the mother, and a reverse correlation has been demonstrated between birth weight and thiocyanate level in cord blood. Cigarette smoking induces similar changes in thyroid function in the adult and the fetus. No separate study has elucidated the effects of cessation of smoking, but there seems to be longstanding effects induced by smoking, some probably irreversible.

Circulating Insulin Concentrations, Smoking, and Alcohol Intake Are Important Independent Predictors of Leptin in Young Healthy Men

“…Both leptin (10) and smoking alter neuroendocrine function (64), cortisol (65), testosterone (66), and thyroid hormone levels (67,68). The precise mechanism by which smoking and alcohol intake act on the adipocyte to regulate leptin levels and the mechanism by which these effects on circulating leptin may affect human physiology will be the subject of future investigation.…”

Effect of passive smoking on thyroid function in infants

“…Among the metabolites, the influence of thiocyanate on thyroid function has received particular attention (5,15,16), both in vivo and in vitro, with conflicting results. Increased TG levels (5, 16), reduced TSH concentrations (17)(18)(19), associated unaltered (17) or increased T 4 concentrations (18), and reduced (16) or normal (19) T 3 concentrations have been reported.…”

Factors associated with serum thyroglobulin in a Ukrainian cohort exposed to iodine-131 from the accident at the Chernobyl Nuclear Plant

“…Several studies have shown cigarette smoking to be associated with increased serum Tg (Bertelsen and Hegedus, 1994;Cahoon et al, 2013;Knudsen et al, 2002;Krejbjerg et al, 2016), and with significant changes to indicators of thyroid dysfunction (including decreased serum TSH, increased thyroid size, and increased risk of prevalent non-toxic goiter and thyroid nodules in iodine deficient areas) Pedersen et al, 2008;Wiersinga, 2013). Increases in serum Tg among smokers have been attributed to thiocyanate-a metabolite of the cigarette smoke component, cyanide, and a competitive inhibitor of thyroidal iodine uptake (Tonacchera et al, 2004).…”