Alterations in Ventricular Structure and Function in Obese Adolescents with Nonalcoholic Fatty Liver Disease

Objective To determine the association among nonalcoholic fatty liver disease (NAFLD), metabolic function, and cardiac function in obese adolescents. Study design Intrahepatic triglyceride (IHTG) content (magnetic resonance spectroscopy), insulin sensitivity and beta-cell function (5-hour oral glucose tolerance test with mathematical modeling), and left ventricular function (speckle tracking echocardiography) were determined in 3 groups of age, sex, and Tanner matched adolescents: (1) lean (n = 14, body mass index [BMI] = 20 +/- 2 kg/m(2)); (2) obese with normal (2.5%) IHTG content (n = 15, BMI = 35 +/- 3 kg/m(2)); and (3) obese with increased (8.7%) IHTG content (n = 15, BMI = 37 +/- 6 kg/m(2 zeta)). Results The disposition index (beta-cell function) and insulin sensitivity index were similar to 45% and similar to 70% lower, respectively, and whole body insulin resistance, calculated by homeostasis model of assessment-insulin resistance (HOMA-IR), was similar to 60% greater, in obese than in lean subjects, and similar to 30% and similar to 50% lower and similar to 150% greater, respectively, in obese subjects with NAFLD than those without NAFLD (P < .05 for all). Left ventricular global longitudinal systolic strain and early diastolic strain rates were significantly decreased in obese than in lean subjects, and in obese subjects with NAFLD than those without NAFLD (P <.05 for all), and were independently associated with HOMA-IR (beta = 0.634). IHTG content was the only significant independent determinant of insulin sensitivity index (beta = -0.770), disposition index (beta = -0.651), and HOMA-IR (beta = 0.738). Conclusions These findings demonstrate that the presence of NAFLD in otherwise asymptomatic obese adolescents is an early marker of cardiac dysfunction.