Introduction: Impaired vascular function and structure has been associated with cardiovascular risk factors such as elevated levels of Low Density Lipoprotein cholesterol (LDL-C) and triglycerides, depressed High Density Lipoprotein cholesterol (HDL-C), elevated blood pressure (BP) and body mass index (BMI) in children and young adults. These changes can result in premature coronary artery disease. The degree to which these measures predict vascular damage in children and adolescents is less clear.
Hypothesis: We hypothesized that commonly used clinical and laboratory measures will predict vascular health as assessed by measures of carotid artery intima-media thickness (CIMT), pulse wave velocity (PWV), and augmentation index (Aix) in at risk youth.
Methods: Children and adolescents with dyslipidemia (n=120, 13.1 ± 1.9 years old, 49% female (59 of 120)) were recruited from a pediatric preventive cardiology clinic. Non-fasting total cholesterol, HDL cholesterol, and triglycerides were obtained prior to the clinic visit. LDL-C and non-HDL-C were calculated with the Martin equation. Remnant particles were calculated as: total cholesterol minus (HDL-C + LDL-C). BP, height, weight, and waist circumference (WC) were measured at the clinic visit. WC was measured 2cm above the iliac crest by a single observer. Tobacco smoke exposure history was obtained using a parent questionnaire. PWV and Aix were measured using a SphygmoCor XCEL combined oscillometric and tonometric device. CIMT was measured via B mode ultrasound on the far wall of the left and right common carotid arteries using a semi-automated edge detection software. Multiple linear regression with backwards selection was used to identify the strongest predictors of CIMT, PWV, and normalized Aix.
Results: Age (β=0.26; p=0.002), systolic BP (β=0.16; p=0.04), waist-to-height ratio (β=0.24; p=0.01), hemoglobin A1c (β=0.18; p=0.01) and presence of hypertriglyceridemic waist (defined as triglycerides ≥110mg/dL and WC ≥90 percentile) (β=0.28; p=0.006) were the strongest predictors of PWV (R2=0.353). Diastolic BP (β=0.21; p=0.01), waist-to-height percentile (β=0.22; p=0.01), and remnant particles (β=0.21; p=0.01) were the strongest predictors of normalized Aix (R2=0.175). Age (β=0.19; p=0.03), and systolic BP (β=0.28; p=0.002) were the strongest predictors of CIMT (R2=0.138). Triglycerides, history of tobacco smoke exposure, total cholesterol, LDL-C, HDL-C, and non-HDL-C were not predictive of CIMT, PWV, or normalized Aix.
Conclusion: BP consistently predicted was the most common predictor of CIMT, PWV, and Aix in children and adolescents with dyslipidemia. Waist-to-height ratio/percentile was also a reliable predictor in both PWV and Aix. BP and abdominal obesity management should be a focus in this at risk population.