015 - Thyroid hormones and obesity
Autor(s): E. Papini, I. Misischi, C. Rovagna, L. Papini, R. Guglielmi
Issue: RIMeL - IJLaM, Vol. 6, N. 3-S1, 2010 (MAF Servizi srl ed.)
Page(s): 15-17
Thyroid hormones induce an increase of both resting and adaptive energy expenditure in experimental models. A significant association between TSH levels and BMI has been reported both in cross-sectional and longitudinal studies both in adults and children. Subclinical hypothyroidism prevalence raises from 1-5% in the general population up to 10-25% in obese patients. Moreover, central fat accumulation is associated with an increase in both FT3 and TSH serum levels. A causative or a secondary role of the observed findings on overweight is still controversial because TSH values decrease in obese children after weight loss. Moreover, TSH and T3 decrease after bariatric surgery. Due to the adverse effects of a small but protracted increase of thyroid hormones on the heart and bone the use of thyroid hormones in obese euthyroid subjects should be strongly discouraged. On the other hand, in hypothyroid patients who are gaining weight thyroid function should be evaluated. In fact, in patients treated with thyroid hormone even small changes in T4 dose can significantly affect REE and influence energy balance and body weight in the long run. Hence, a fine tuning of T4 therapy is necessary in chronic thyroiditis or after thyroidectomy and complains of weight gain should be considered as a possible change in patient energy balance.