Sensitivity to Thyroid Hormone Indices Are Closely Associated With NAFLD

BackgroundPrevious studies on the association between thyroid function and non-alcoholic fatty liver disease (NAFLD) have contradicted. Acquired resistance to thyroid hormone theory might provide a reasonable explanation for these contradictions. We aimed to analyze the association between sensitivity to thyroid hormone indices with NAFLD. MethodsA total of 4,610 individuals from the health medical center of the First Hospital of China Medical University were included in this study. The previously used thyroid feedback quantile-based index (TFQI(FT4)) was calculated. Also, we substituted free triiodothyronine (FT3) into the TFQI formulas to get the TFQI(FT3) index. NAFLD was defined using abdominal ultrasound. ResultsStudy results showed that FT3/FT4 and TFQI(FT3) were positively correlated with the triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) levels (P<0.05) and negatively correlated with high-density lipoprotein cholesterol (HDL-C) level (P<0.05). In contrast, TFQI(FT4) was positively correlated with HDL-C level (P < 0.05). After adjustment for multiple confounders, FT3, FT3/FT4, and TFQI(FT3) were positively associated with the risks of dyslipidemia and NAFLD (P < 0.05). TFQI(FT3) and FT3/FT4 performed better than TFQI(FT4) on ROC analyses for NAFLD prediction, although the diagnostic sensitivity and specificity at the optimal cut-points were low. However, no association was observed between TFQI(FT4) with the risks of dyslipidemia and NAFLD. ConclusionTFQI(FT3) and FT3/FT4 can be used as new indicators for predicting dyslipidemia and NAFLD, although with low sensitivity and specificity at the optimal cut-points, while TFQI(FT4) has insufficient evidence in predicting dyslipidemia and NAFLD.

Automated summary

FT3/FT4 and TFQI(FT3) were positively correlated with TG, TC, and LDL-C levels, and negatively correlated with HDL-C level. FT3, FT3/FT4, and TFQI(FT3) were positively associated with dyslipidemia and NAFLD. TFQI(FT3) and FT3/FT4 performed better in predicting NAFLD compared to TFQI(FT4), but had low sensitivity and specificity at the optimal cut-points. TFQI(FT4) showed no association with dyslipidemia and NAFLD.