There exists close relationship between thyroid function and obesity. Laparoscopic sleeve gastrectomy (LSG) is an effective bariatric surgery in weight loss and obesity-associated comorbidities. However, only a few studies involve in the alteration of thyroid hormones after LSG with inconsistent results. This study aimed to investigate the impact of LSG on thyroid function profiles in Chinese euthyroid obese subjects. A retrospective study was performed of prospectively collected data in 36 obese patients (17 males and 19 females) who underwent LSG. Thyroid function profiles (TT4, FT4, TT3, FT3 and TSH, all within normal reference ranges), anthropometric data, and glucose-lipid metabolic parameters were recorded at baseline, 3 and 6 months after LSG (abbreviated as 3M/6M Post-LSG). Correlations between TSH with other parameters were evaluated. In all individuals, BMI was dramatically decreased at 3M/6M Post-LSG accompanied by decreased fasting blood glucose, fasting insulin, fasting C-peptide, triglyceride and increased HDL-c (P<0.01 or P<0.05). FT3, FT4 and TT3 without TT4 levels were gradually declined from baseline to 6M Post-LSG (P<0.01 or P<0.05, with slight changes in numerical values and still within their normal reference ranges). TSH levels remained unchanged at 3M/6M Post-LSG compared with baseline. In females, the TSH decrease (δTSH) was positively correlated with BMI decrease (δBMI, P<0.05), percentage of total weight loss (%TWL, P<0.01), and percentage of excess weight loss (%EWL, P=0.051, approximately significant) at 6M Post-LSG, while no correlation was observed in males.
In summary, we speculate that euthyroid obese subjects are adept at preserving their thyroid function homeostasis despite of morbid obesity at baseline as well as dramatic weight loss and significant improvement of glucose-lipid metabolism after LSG. In addition, δBMI/%TWL/%EWL may be the predictor of improved TSH levels after LSG in female but not male obese patients.
L. Li: None. X. Wang: None. J. Gao: None. S. Qu: None.