Abstract
ObjectiveBariatric surgery has become the most effective treatment for morbid obesity. Increasing evidence showed that bariatric surgery can alleviate insulin resistance and influence thyroid function. This study aimed to investigate the relationship between changes in thyroid function and adipose tissue insulin resistance (adipo-IR) after bariatric surgery.Methods A total of 287 non-diabetic participants with regular thyroid function were recruited and divided into the lean, overweight and obese groups. Among them, 50 morbidly obese patients submitted to bariatric surgery.ResultsThe obese group had a higher level of adipo-IR, thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), FT3/free thyroxine (FT4) and metabolism disorders than the lean and overweight groups. BMI was correlated with TSH, FT3, FT3/FT4 and adipo-IR (r = 0.309, 0.315, 0.322 and 0.651, respectively, all P < 0.001). Adipo-IR was significantly correlated with TSH (r = 0.402, P < 0.001), FT3 (r = 0.309, P < 0.001), and FT3/FT4 (r = 0.228, P < 0.05). Bariatric surgery resulted in a sharp decline in BMI, adipo-IR, TSH, FT3 and FT3/FT4 levels, meanwhile, metabolic disorders improved. The decrease in BMI after bariatric surgery was significantly correlated with reductions in adipo-IR (r = 0.577, P < 0.001) and TSH (r = 0.401, P = 0.005). Interestingly, the fasting blood glucose, fasting insulin, adipo-IR and TSH in the higher TSH group decreased more remarkably than in the lower TSH group.ConclusionObese individuals with higher TSH levels had an obvious metabolic improvement after bariatric surgery.
Highlights
The morbidity of overweight and obesity has increased globally (1)
This study showed that participants from lean to obesity, metabolism disorders were increased, and adipo-insulin resistance (IR), thyroid-stimulating hormone (TSH), FT3, FT3/FT4 and thyrotroph T4 resistance index (TT4RI) were significantly increased
We found a linear correlation between BMI, TSH and adipo-IR at baseline, which was consistent with the relationship among changes in BMI, TSH and adipo-IR before and after bariatric surgery
Summary
The morbidity of overweight and obesity has increased globally (1). During 2013–2014 in the United States, obesity was 40.4% among women and 35% among men. The corresponding incidences for morbid obesity were 9.9% for women and 5.5% for men (2). Obesity is an independent risk factor for insulin resistance (IR), metabolic syndrome and type 2 diabetes (T2D). Lifestyle interventions and medication fail to reduce body weight durably, bariatric surgery is the most effective way to lose weight and exert beneficial effects on metabolism (3).
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