Thyroid Function and Non-alcoholic Fatty Liver Disease in Children and Adolescent With Obesity: A Systematic Review and Meta-Analysis.

OBJECTIVE

The relationship between thyroid function and non-alcoholic fatty liver disease (NAFLD) in pediatric obesity remains incompletely defined. This systematic review and meta-analysis aimed to quantitatively assess the association between thyroid function parameters and NAFLD in children and adolescents with obesity.

METHODS

A systematic search of PubMed/MEDLINE, Scopus, and Web of Science was conducted through December 31, 2025. Observational studies evaluating thyroid function in children and adolescents with obesity, stratified by the presence or absence of NAFLD, were included. Hepatic steatosis was diagnosed using imaging, histology, or validated noninvasive scores. Random-effects meta-analyses were performed to compare serum thyroid-stimulating hormone (TSH), free thyroxine, and free triiodothyronine levels between groups. Study quality was assessed using Quality Assessment of Diagnostic Accuracy Studies version 2.

RESULTS

Ten studies encompassing 5145 participants were included. Meta-analysis of 6 studies (n= 3076) demonstrated significantly higher TSH levels in patients with NAFLD compared with controls without NAFLD (mean difference 0.37 mIU/L; 95% confidence interval [CI] 0.07-0.66), with moderate heterogeneity (I2= 48.7%). No significant differences were observed for free thyroxine (standardized mean difference -0.35; 95% CI -1.15 to 0.45) or free triiodothyronine (standardized mean difference 0.35; 95% CI -0.26 to 0.96). Sensitivity analyses confirmed the robustness of the TSH association.

CONCLUSION

In pediatric obesity, NAFLD is associated with higher TSH levels in the absence of significant changes in circulating thyroid hormone concentrations. These findings suggest that hyperthyrotropinaemia may represent a metabolic marker of hepatic steatosis rather than an adaptive physiological response. Prospective studies are needed to clarify causality and clinical implications.