Visceral and subcutaneous adipose tissue,which one induced thyroid dysfunction in patients with morbid obesity

BackgroundThyroid dysfunction in patients with morbid obesity usually resolves after bariatric surgery. However, the role of diverse types of adipose tissue in the process remains unknown.ObjectivesWe aim to investigate the effects of visceral and subcutaneous fat on thyroid function in a Chinese population with morbid obesity who underwent sleeve gastrectomy (SG).SettingUniversity hospital, Shanghai, ChinaMethodsRepeated measurement data of thyroid hormone and body fat were collected at 0, 3, 6, 12, 24, and 36 months after sleeve gastrectomy. Dual-energy X-ray absorptiometer and quantitative computerized tomography (CT) were used to compute visceral fat and subcutaneous fat. Repeated measures correlation (rmmcorr) package was employed for correlation analysis with generalized additive mixed model (GAMM) determining the independent factors.ResultsThyroid stimulating-hormone (TSH) showed notable decrease at 36 months after surgery, coupled with reduction of BMI (38.08 kg/cm² versus 24.28 kg/cm²), C-reactive protein (CRP), visceral adipose tissue (786.74 cm² versus 367.44 cm²), body fat rate, and waistline (118.13 cm versus 100.87 cm). Only visceral fat, diabetes, and CRP proved to be independent variables for TSH decline, without correlation with subcutaneous fat.ConclusionThe present study is first to report the effects of different types of body fat on thyroid function in a Chinese population with morbid obesity, revealing that loss of visceral fat is the key to improving endocrine and metabolic activity after bariatric surgery.