Laparoscopic Sleeve Gastrectomy: Impact on Body Mass Index and Thyroid Hormones in Euthyroid Obese Patients

BACKGROUND Obesity is still a major global public health problem and its incidence is increasing. Obesity leads to deterioration in thyroid functions. Even when they are within normal ranges, high normal levels of thyroid-stimulating hormone (TSH) increase morbidity and mortality. This study aimed to evaluate the body mass index (BMI) and TSH levels in 300 euthyroid patients with obesity before and after laparoscopic sleeve gastrectomy (LSG). MATERIAL AND METHODS A total of 300 euthyroid patients who underwent LSG between 2019 and 2021 were included in the study. Body mass index (BMI), thyroid-stimulating hormone (TSH), and free triiodothyronine (FT) 3 and tetraiodothyronine (FT4) levels were recorded before surgery and at 6 and 12 months after surgery and subsequently analyzed. RESULTS Mean BMI values were significantly lower at 6 and 12 months after surgery (P<0.001). There was a significant difference between mean TSH and FT4 levels before surgery and those at 6 and 12 months after surgery (P<0.001). However, mean FT3 levels remained unchanged 1 year after surgery (P=0.005). CONCLUSIONS LSG is not only effective in terms of weight loss, but also exhibits improving effects on thyroid hormone homeostasis in obese patients and provides protection against further adverse effects of TSH.