Early Metabolic and Cardiovascular Alterations in Adolescents with MASLD or Simple Obesity

Background: Hepatic steatosis is a frequent complication of adolescent obesity, but its association with metabolic and cardiovascular alterations beyond those related to obesity itself remains unclear. The primary objective of this study was to compare metabolic, hepatic, and cardiovascular characteristics among adolescents with obesity and hepatic steatosis (metabolic dysfunction-associated steatotic liver disease, MASLD), adolescents with obesity without hepatic steatosis, and healthy controls. The secondary, exploratory objective was to assess whether commonly used insulin resistance-related indices could discriminate MASLD from obesity without hepatic steatosis. Methods: This cross-sectional study included 111 adolescents aged 14–18 years: 50 with obesity and MASLD (controlled attenuation parameter [CAP] >250 dB/m on transient elastography), 33 with obesity without hepatic steatosis (CAP ≤250 dB/m or inferred from normal weight status and absence of liver disease), and 28 healthy controls. CAP was available in 92 of 111 participants (49/50 MASLD, 22/33 obesity without steatosis, 21/28 controls). Assessments included anthropometry, bioimpedance-based body composition, liver enzymes, lipid profile, glucose–insulin metabolism, insulin resistance-related indices (HOMA-IR, TyG, VAI, TyG-BMI, and TyG-WC), pulse wave velocity (PWV), aortic blood pressure, carotid ultrasound, and echocardiography. Results: Compared with adolescents with obesity without steatosis, those with MASLD had higher CAP, alanine aminotransferase, gamma-glutamyl transferase, triglyceride levels, and waist circumference (p < 0.05), whereas surrogate insulin resistance indices did not differ significantly between the two groups. Compared with healthy controls, both clinical groups had higher left ventricular mass index and relative wall thickness (p < 0.05). PWV was higher in the MASLD group than in both controls (p = 0.030) and in adolescents with obesity without steatosis (p = 0.028), whereas carotid intima-media thickness did not differ significantly across groups. In receiver operating characteristic analyses, all evaluated insulin resistance-related indices showed poor discrimination between MASLD and obesity without hepatic steatosis, with AUC values ranging from 0.501 to 0.569. Waist circumference SDS was an important independent correlate of left ventricular mass index in regression analysis. Conclusions: Among adolescents with obesity, MASLD was associated with a less favorable hepatic and lipid profile and differences in selected cardiovascular measures. Waist circumference SDS was an important independent correlate of left ventricular mass index, highlighting the relevance of central adiposity in the assessment of cardiovascular characteristics. Commonly used surrogate insulin resistance-related indices showed poor ability to distinguish MASLD from obesity without hepatic steatosis and should not be used as standalone tools for this purpose. These findings support the complementary role of anthropometric, biochemical, cardiovascular, and noninvasive hepatic assessments in the evaluation of adolescents with obesity.