Effect of Weight Loss after Bariatric Surgery on Thyroid-Stimulating Hormone Levels in Euthyroid Patients with Morbid Obesity.

Paula Juiz-Valiña, Elena Outeiriño-Blanco, Sonia Pértega, Bárbara María Varela-Rodriguez, María Jesús García-Brao, Enrique Mena, Lara Pena-Bello, María Cordido, Susana Sangiao-Alvarellos, Fernando Cordido

Journal: Nutrients 2019;11(5):1121

PMID: 31137484

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Plain Language Summary

Obesity is associated with many health issues, including thyroid problems. The aim of this observational study was to investigate the effect of weight loss surgery on thyroid hormones. 129 morbidly obese people with normal thyroid function were included in the study. 12 months after weight loss surgery, the levels of thyroid stimulating hormone (TSH) had significantly decreased from 3.3 to 2.1 µU/mL. Levels of the thyroid hormone free thyroxine (T4) also significantly decreased from 1.47 to 1.12 ng/dL. Those that lost more weight following surgery tended to have a greater reduction in TSH. Fasting blood glucose also significantly improved after surgery. The authors concluded that obesity is associated with raised TSH levels, and this makes diagnosing thyroid problems in people with morbid obesity more complicated.

Abstract

Obesity is associated with several endocrine abnormalities, including thyroid dysfunction. The objective of this study was to investigate the effect of weight loss after bariatric surgery on thyroid-stimulating hormone (TSH) levels in euthyroid patients with morbid obesity. We performed an observational study, evaluating patients with morbid obesity submitted to bariatric surgery. We included 129 patients (92 women) and 31 controls (21 women). Clinical, anthropometric, biochemical, and hormonal parameters were evaluated. The primary endpoint was circulating TSH (µU/mL). Fasting TSH levels were higher in the obese group (3.3 ± 0.2) than in the control group (2.1 ± 0.2). The mean excessive body mass index (BMI) loss (EBMIL) 12 months after bariatric surgery was 72.7 ± 2.1%. TSH levels significantly decreased in the obese patients after surgery; 3.3 ± 0.2 vs. 2.1 ± 0.2 before and 12 months after surgery, respectively. Free thyroxine (T4) (ng/dL) levels significantly decreased in the obese patients after surgery; 1.47 ± 0.02 vs. 1.12 ± 0.02 before and 12 months after surgery, respectively. TSH decreased significantly over time, and the decrement was associated with the EBMIL. In euthyroid patients with morbid obesity, weight loss induced by bariatric surgery promotes a significant decline of the increased TSH levels. This decrement of TSH is progressive over time after surgery and significantly associated with excess BMI loss.

Address: Endocrine, Nutritional and Metabolic Diseases Group, Faculty of Health Sciences, University of A Coruña, 15006 A Coruña, Spain. [email protected].; Instituto de Investigación Biomedica (INIBIC), University Hospital A Coruña, 15006 A Coruña, Spain. [email protected].; Department of Endocrinology, University Hospital A Coruña, 15006 A Coruña, Spain. [email protected].; Clinical Epidemiology and Biostatistics Unit, University Hospital A Coruña, 15006 A Coruña, Spain. [email protected].; Endocrine, Nutritional and Metabolic Diseases Group, Faculty of Health Sciences, University of A Coruña, 15006 A Coruña, Spain. [email protected].; Instituto de Investigación Biomedica (INIBIC), University Hospital A Coruña, 15006 A Coruña, Spain. [email protected].; Department of Digestive and General Surgery, University Hospital A Coruña, 15006 A Coruña, Spain. [email protected].; Department of Digestive and General Surgery, University Hospital A Coruña, 15006 A Coruña, Spain. [email protected].; Endocrine, Nutritional and Metabolic Diseases Group, Faculty of Health Sciences, University of A Coruña, 15006 A Coruña, Spain. [email protected].; Instituto de Investigación Biomedica (INIBIC), University Hospital A Coruña, 15006 A Coruña, Spain. [email protected].; Endocrine, Nutritional and Metabolic Diseases Group, Faculty of Health Sciences, University of A Coruña, 15006 A Coruña, Spain. [email protected].; Instituto de Investigación Biomedica (INIBIC), University Hospital A Coruña, 15006 A Coruña, Spain. [email protected].; Endocrine, Nutritional and Metabolic Diseases Group, Faculty of Health Sciences, University of A Coruña, 15006 A Coruña, Spain. [email protected].; Instituto de Investigación Biomedica (INIBIC), University Hospital A Coruña, 15006 A Coruña, Spain. [email protected].; Endocrine, Nutritional and Metabolic Diseases Group, Faculty of Health Sciences, University of A Coruña, 15006 A Coruña, Spain. [email protected].; Instituto de Investigación Biomedica (INIBIC), University Hospital A Coruña, 15006 A Coruña, Spain. [email protected].; Department of Endocrinology, University Hospital A Coruña, 15006 A Coruña, Spain. [email protected].

DOI: 10.3390/nu11051121

Patient Centred Factor

Mediators: Obesity

Clinical Imbalances

Hormonal

Laboratory Testing

Blood

Nutrition Evidence Keywords

Obesity Overweight Weight loss TSH Thyroid Stimulating Hormone Thyroxine Thyroid Bariatric surgery Weight loss surgery T4 Morbid obesity

Bioactive Substances

TSH T4 Blood glucose Thyroxine Thyroid stimulating hormone

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Medical:

https://medlineplus.gov/weightcontrol.html

MeSH Terms: Adult, Bariatric Surgery, Biomarkers, Body Mass Index, Female, Humans, Male, Middle Aged, Obesity, Morbid, Retrospective Studies, Thyroid Gland, Thyrotropin, Time Factors, Treatment Outcome, Weight Loss