The Effect of Sleeve Gastrectomy on the Function and Volume of the Thyroid Gland

Background: This study aimed to reveal changes in thyroid gland volume and functions in patients having undergone sleeve gastrectomy (SG). Methods: In this retrospective cohort study, the thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) levels of 48 morbidly obese patients who underwent SG operations were examined within the last 1 year before the operation and in the sixth month after the operation and then compared. The volume of the thyroid gland and, if present, nodules of patients were also calculated through ultrasonographic measurements before and after SG. Results: It was determined that there was a decrease in fT3 and TSH levels, but an increase in fT4 levels, in the postoperative period. There was no significant difference in thyroid volume change. In addition, it was observed that the difference in weight before and after the operation was inversely proportional to the nodule width and average nodule size (p = 0.05 and p = 0.033). Conclusions: We have shown that there were some changes in the thyroid function tests carried out in the sixth month following SG compared with the preoperative period, but there was no statistically significant difference in the thyroid gland and nodule volumes.