BACKGROUND: The pathophysiologic relationship between morbid obesity and thyroid hormones is not well understood. The goal of this study was to evaluate the influence of obesity and weight reduction after bariatric surgery on thyroid hormone levels. METHODS: Patients who underwent gastric bypass or adjustable gastric banding at our institution, had no previous diagnosis of thyroid disorder, were not taking medication that could affect the thyroid function evaluation, and who were nonsmokers were included in this retrospective evaluation. The association between the thyroid-stimulating hormone (TSH) and free thyroxine (T(4)) levels and body mass index (BMI), and the influence of weight loss after bariatric surgery on these hormones were investigated at different points (preoperatively and 6 and 12 months after bariatric surgery). RESULTS: A total of 86 patients met the study criteria. The TSH levels correlated positively with BMI (P <.001, r = .91) within the BMI range of 30-67 kg/m(2). The mean BMI change from 49 to 32 kg/m(2) after bariatric surgery was associated with a mean reduction in the TSH level from 4.5 to 1.9 microU/mL. Free T(4) showed no association with BMI and was not significantly influenced by weight loss. Before bariatric surgery, 10.5% of the subjects had laboratory values consistent with subclinical hypothyroidism. After bariatric surgery, 100% of these patients experienced significant weight reduction with simultaneous resolution of their subclinical hypothyroidism. CONCLUSION: The results of our study have demonstrated a statistically significant positive association between serum TSH within the normal range and BMI. No association was found between BMI and free T(4) serum levels. The prevalence of subclinical hypothyroidism in study group was 10.5%. Weight loss after bariatric surgery improved or normalized thyroid hormone levels.
BACKGROUND: The pathophysiologic relationship between morbid obesity and thyroid hormones is not well understood. The goal of this study was to evaluate the influence of obesity and weight reduction after bariatric surgery on thyroid hormone levels. METHODS:Patients who underwent gastric bypass or adjustable gastric banding at our institution, had no previous diagnosis of thyroid disorder, were not taking medication that could affect the thyroid function evaluation, and who were nonsmokers were included in this retrospective evaluation. The association between the thyroid-stimulating hormone (TSH) and free thyroxine (T(4)) levels and body mass index (BMI), and the influence of weight loss after bariatric surgery on these hormones were investigated at different points (preoperatively and 6 and 12 months after bariatric surgery). RESULTS: A total of 86 patients met the study criteria. The TSH levels correlated positively with BMI (P <.001, r = .91) within the BMI range of 30-67 kg/m(2). The mean BMI change from 49 to 32 kg/m(2) after bariatric surgery was associated with a mean reduction in the TSH level from 4.5 to 1.9 microU/mL. Free T(4) showed no association with BMI and was not significantly influenced by weight loss. Before bariatric surgery, 10.5% of the subjects had laboratory values consistent with subclinical hypothyroidism. After bariatric surgery, 100% of these patients experienced significant weight reduction with simultaneous resolution of their subclinical hypothyroidism. CONCLUSION: The results of our study have demonstrated a statistically significant positive association between serum TSH within the normal range and BMI. No association was found between BMI and free T(4) serum levels. The prevalence of subclinical hypothyroidism in study group was 10.5%. Weight loss after bariatric surgery improved or normalized thyroid hormone levels.
Authors: Jacqueline Jonklaas; Antonio C Bianco; Andrew J Bauer; Kenneth D Burman; Anne R Cappola; Francesco S Celi; David S Cooper; Brian W Kim; Robin P Peeters; M Sara Rosenthal; Anna M Sawka Journal: Thyroid Date: 2014-12 Impact factor: 6.568
Authors: João Sérgio Neves; Sofia Castro Oliveira; Pedro Souteiro; Jorge Pedro; Daniela Magalhães; Vanessa Guerreiro; Rita Bettencourt-Silva; Maria Manuel Costa; Ana Cristina Santos; Joana Queirós; Ana Varela; Paula Freitas; Davide Carvalho Journal: Obes Surg Date: 2018-01 Impact factor: 4.129
Authors: Margaret C Garin; Alice M Arnold; Jennifer S Lee; Russell P Tracy; Anne R Cappola Journal: J Clin Endocrinol Metab Date: 2014-01-16 Impact factor: 5.958
Authors: Jeffrey I Mechanick; Adrienne Youdim; Daniel B Jones; W Timothy Garvey; Daniel L Hurley; M Molly McMahon; Leslie J Heinberg; Robert Kushner; Ted D Adams; Scott Shikora; John B Dixon; Stacy Brethauer Journal: Obesity (Silver Spring) Date: 2013-03 Impact factor: 5.002
Authors: Jeffrey I Mechanick; Adrienne Youdim; Daniel B Jones; W Timothy Garvey; Daniel L Hurley; M Molly McMahon; Leslie J Heinberg; Robert Kushner; Ted D Adams; Scott Shikora; John B Dixon; Stacy Brethauer Journal: Endocr Pract Date: 2013 Mar-Apr Impact factor: 3.443