Modified triglyceride-glucose indices as novel predictors of metabolic dysfunction-associated fatty liver disease in US adolescents: a nationally representative study from NHANES 2017-2020.

Abstract

Background: Metabolic dysfunction-associated fatty liver disease (MAFLD) has become the most prevalent chronic liver condition in adolescents. The triglyceride-glucose (TyG) index, a surrogate marker of insulin resistance, has shown promise in adult MAFLD detection but requires pediatric-specific validation, particularly when combined with anthropometric measures. This study investigated the association between modified TyG indices and MAFLD, and evaluated their predictive value in adolescents.

Methods: This cross-sectional study analyzed data from 532 adolescents (12-18 years) in the 2017-2020 National Health and Nutrition Examination Survey (NHANES) with complete records. MAFLD diagnosis was based on transient elastography plus metabolic criteria. The investigators employed multivariate linear regression and restricted cubic splines (RCS) to examine linear and nonlinear relationships between modified TyG indices and CAP values. Subgroup analyses were stratified by obesity status, and sensitivity analyses were performed on the NAFLD cohort (n = 527). Receiver operating characteristic (ROC) curve analysis, using Youden's index, evaluated the predictive performance of TyG indices for MAFLD identification.

Results: Among 130 MAFLD adolescents (vs 402 controls), modified TyG indices demonstrated significantly stronger associations with CAP in fully adjusted models compared to the original TyG index. TyG-WC showed the highest diagnostic accuracy (AUC = 0.923, 95%CI:0.900-0.947), followed by TyG-BMI (AUC = 0.917) and TyG-WHtR (AUC = 0.915), while the original TyG index performed poorly (AUC = 0.673). Subgroup analyses revealed particularly strong associations in non-obese participants, and sensitivity analyses confirmed result robustness after excluding potential confounders. Optimal cutoff values provided clinically useful screening thresholds, with TyG-WC achieving 94% sensitivity at 665.94.

Conclusion: This study demonstrates that modified TyG indices incorporating anthropometric parameters (particularly TyG-WC) significantly outperform the original TyG index for MAFLD detection in adolescents, with superior diagnostic accuracy (AUC 0.915-0.923). The robust predictive performance maintained in sensitivity analyses and non-obese subgroups supports their clinical utility as simple, non-invasive screening tools for pediatric MAFLD risk stratification.