284-LB: From Metabolically Healthy Obesity (MHO) to Metabolically Unhealthy Obesity (MUHO)—Decreased Thyroid Hormone Sensitivity

Abstract

Background: To explore the difference of thyroid hormone sensitivity between metabolically healthy and metabolically unhealthy obesity patients and its influence on obesity phenotype. Methods: 10927 euthyroid adults were enrolled, 4 groups based on the presence/absence of metabolic disorders (MD) and BMI were divided: 1) NC (n=1441): no MD and 22≤BMI < 25Kg/m2. 2) NMu (n=3765): MD and 22≤BMI < 25Kg/m2. 3) MHO (n=148): obese with no MD (BMI≥28Kg/m2). 4) MuHO (n=1981): obese with MD (BMI≥28Kg/m2). MD was defined as meeting none of the following criteria: fasted blood glucose ≤6.1 mmol/L; triglycerides ≥1.7 mmol/L; high density lipoprotein (HDL) <1.0 mmol/L (male) and <1.3 mmol/L (female); elevated SBP (≥130 mmHg) or/and DBP (≥85 mmHg). Thyroid hormone central sensitivity indices were calculated by thyroid feedback quantile-based index (TFQI), TSH index (TSHI), Chinese-referenced parametric TFQI (PTFQI) and thyrotropin thyroxine resistance index (TT4RI). Peripheral thyroid hormone sensitivity was evaluated by FT3/FT4 ratio. Results: Compared with MHO group, TFQI, PTFQI and TT4RI elevated in MuHO group, and the trend still existed after adjusting for confounding factors. High FT3/FT4 ratio was an independent risk factor for MuHO (OR = 1.22, 95%CI: 1.13, 1.37, P<0.001). In euthyroid obese patients, decreased TFQI was a protective factor for MHO (OR=0.71, 95%CI 0.51, 0.83, P=0.036), while TSHI (OR= 1.27, 95%CI: 1.11, 1.38, P =0.027) and TT4RI (OR= 1.08, 95%CI: 1.03, 1.16, P =0.022) were significantly correlated with the occurrence of MuHO. Conclusions: Thyroid hormone sensitivity is impaired with elevated BMI. Impaired thyroid hormone sensitivity associated with the development of metabolically unhealthy obesity in patients with similar BMI. Keywords Metabolically Healthy Obesity, Thyroid Hormone Sensitivity Disclosure N. Zhang: None. G. Wang: None. Funding National Natural Science Foundation of China (81770792)