Abstract
Background/Objectives: Sex differences in metabolic dysfunction-associated steatotic liver disease (MASLD) have been established in adult males; however, data on paediatric populations remain scarce. This study aimed to elucidate the sex-specific correlations of serum uric acid (SUA), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels with MASLD in children with obesity. Methods: Clinical data from 262 children with obesity were retrospectively analysed. Participants were categorised by sex and MASLD status (MASLD+ vs. MASLD-). Laboratory tests, including ALT, AST, SUA, fasting glucose, glycated haemoglobin, lipid profile, and insulin levels, were compared. Comparison of significant influencing factors of obesity in children with non-alcoholic fatty liver disease was conducted using multivariable logistic regression analysis by sex. Results: Hyperinsulinemia was significantly associated with MASLD in all children. Sex-based analyses revealed differentiated patterns. In males, elevated SUA (p = 0.008) and ALT (p < 0.05) were independently associated with MASLD; however, in females, only elevated AST (p = 0.003) was significantly associated. Conclusions: While insulin resistance is a common risk factor for MASLD in all children with obesity, this study suggests that its manifestation may differ by sex. Elevated SUA and ALT levels may serve as sex-specific indicators in males, while elevated AST levels appear more relevant in females. These findings support the potential value of sex-specific metabolic markers in early MASLD screening, although further validation is needed.