Influence of the degree of obesity in obese euthyroid: An observational study of the correlation between body mass index (BMI) and thyroid stimulating hormone (TSH) in patients undergoing bariatric surgery.

Abstract

Abstract Objective: Although controversial, there may be a positive correlation between the body mass index (BMI) of individuals with obesity in euthyroidism and serum levels of thyroid stimulating hormone (TSH). This study aimed to evaluate the correlation between BMI and serum levels of TSH in individuals with morbid obesity undergoing bariatric surgery. Patients and methods: The medical records of patients treated between the years 2012 and 2016 were used. A total of 96 patients with obesity, pre-surgery BMI ≥ 40 kg/m2, being followed up in the endocrinology unit, with mean age of 50 years, were evaluated pre and post operatively. In addition to the plasma TSH dosage by IRMA and plasma free T4 by RIE, age, BMI and biochemical parameters (glycaemia, total cholesterol and triglycerides) were analyzed. Results: Patients with BMI > 40 kg/m2 prior to surgery showed higher serum TSH than subjects with a BMI <40 kg/m after surgery (2.48 ± 0.2 vs. 1.81 ± 0.25, p < 0.001). The decrease in BMI was accompanied by an improvement in the glycemic and lipid profiles, as well as free T4 and TSH levels are shown to accompany BMI. Conclusion: Bariatric surgery was efficient in controlling obesity, since 100% of the patients had their degree of obesity decreased with concomitant metabolic improvement. We found that BMI and TSH are positively related, as post-surgical patients had both BMI and TSH decreased.