Associations of Insulin Resistance and Glycemia with Liver Enzymes in Hispanic/Latino Youths

Background: Associations of insulin resistance and hyperglycemia with a panel of liver enzymes have not been well studied in a young, heterogenous Hispanic/Latino population. We aimed to assess the associations of insulin resistance and glycemia with nonalcoholic fatty liver disease (NAFLD), as measured by liver enzymes and the pediatric NAFLD fibrosis index (PNFI), and whether these associations are modified by body mass index and mediated by inflammation or endothelial dysfunction. Materials and Methods: We conducted a cross-sectional study of 1317 boys and girls aged 8 to 16 years from the Hispanic Community Children's Health Study/Study of Latino Youth. We used Poisson regression to assess the associations of fasting glucose, hemoglobin A1c, and homeostasis model assessment of insulin resistance (HOMA-IR) with elevated alanine aminotransferase (ALT) (>25 U/L in boys, >22 U/L in girls), aspartate aminotransferase (AST) (≥37 U/L), gamma-glutamyl transpeptidase (GGT) (≥17 U/L), and PNFI (≥9; a function of age, waist circumference, and triglyceride level). Results: HOMA-IR was associated with elevated ALT, AST, GGT, and PNFI [prevalence ratios (95% confidence intervals) for each 1-unit increase in the natural log of HOMA-IR: 1.99 (1.40-2.81), 2.15 (1.12-4.12), 1.70 (1.26-2.30), and 1.98 (1.43-2.74), respectively]. Associations were observed in overweight/obese children, but not in normal weight children (P-interaction=0.04 for AST and P-interaction=0.07 for GGT). After further adjustment for adiponectin, high-sensitivity C-reactive protein, e-selectin, and PAI-1, associations of HOMA-IR with liver enzymes and PNFI were attenuated, but remained statistically significant for AST and PNFI. Conclusion: Insulin resistance was associated with NAFLD in overweight/obese Hispanic/Latino youth, and this association may be partially mediated by inflammation and endothelial dysfunction.