Impaired Vascular Function in Obese Adolescents with Insulin Resistance

Objective To evaluate endothelial function (EF) in a cohort of obese adolescents with impaired insulin sensitivity. Study design Cardiovascular risk factors and adipocytokines, along with digital hyperemia, were evaluated by peripheral arterial tonometry (PAT) in adolescents with obesity and insulin resistance (IR) in relation to healthy, nonobese controls. Results The obese and control subjects were of similar age (13.4 ± 1.7 years vs 14.0 ± 1.4 years) and sex. The obese subjects had IR (mean homeostasis model of assessment [HOMA] score = 5.4; 95% confidence interval = 3.3-7.5) and significantly greater body mass index (BMI) (BMI z -score 2.4 ± 0.2 kg/m2 vs 0.0 ± 0.8 kg/m2 ) and waist circumference (WC) measures (109.6 ± 11.1 cm vs 70.5 ± 9.4 cm) with elevated low-density lipoprotein cholesterol (LDL-C), triglyceride, and high-sensitivity C-reactive protein levels. The mean PAT ratio was significantly lower in obese adolescents compared with controls (1.51 ± 0.4 vs 2.06 ± 0.4; P = .002), indicative of impaired EF. Linear regression demonstrated associations between PAT ratio and BMI, WC, age, and LDL-C but not between PAT and leptin, resistin, or adiponectin levels or IR. Conclusions Obese adolescents with IR exhibited significantly worse EF as assessed by PAT compared with healthy, nonobese controls, and EF showed a significant association with measures of adiposity and other cardiovascular risk factors.