Comparison of Carotid Intima-Media Thickness in Pediatric Patients with Insulin Resistance Syndrome, Heterozygous Familial Hyperlipidemia, and Healthy Control Patients*

Synopsis: Common carotid artery intima-media thickness (CIMT) is the distance between the luminal-intima and media-advential interfaces. Elevated CIMT is caused by intimal thickening or lipid deposition in this space and is an independent risk factor for coronary artery disease and a marker for early atherosclerosis. Pediatric populations at risk for increased CIMT include insulin resistance syndrome (IRS), familial hyperlipidemia (FH), or patients with a combination of IRS and FH (IRS+FH). Purpose: Our goal was to compare CIMTs of these three groups with one another and against a control group consisting of healthy, normal-weight children to identify the greatest risk group for early atherosclerosis. Methods: Our population consisted of pediatric patients (ages 5-20 years) who were evaluated between February 2008 and May 2010 and had their CIMT measured in a standardized manner for clinical indication. CIMT measurements were performed by ultrasonographers experienced in CIMTwho used the same machine. Records were randomly chosen retrospectively for IRS and FH patients, but an active search was required to identify individuals with IRS+FH. Results: CIMT for 90 patients were included in this study, 57 from patients with IRS, 23 for FH, and 10 with IRS+FH. The control group consisted of 84 healthy volunteers of the same age range. Mean CIMT for the IRS group was 472.6 mm (SD, 70), 443.8 mm (SD, 61) for the FH group, 478.3 mm (SD, 70) for the IRS+FH group, and 423.2 mm (SD, 45) for the control group. Significance differences between groups were assessed with a series of unpaired t tests. FH versus IRS (P 5 .011), FH vs. IRS+FH (P 5 .65), FH vs. control (P 5 .038), IRS vs. IRS+FH (P 5 .74), IRS vs. control (P 5 .3.4 ! E), and IRS+FH vs. control (P 5 .003). Multiple regression analysis showed significant negative correlation between HDL and CIMT (r 5 -0.333, P 5 .012). No other measured variable (low-density lipoprotein, triglycerides, blood pressure, waist circumference, or body mass index) showed statistically significant correlation with CIMT. Conclusions: In pediatric patients the greatest increase in CIMT occurred for IRS alone or for IRS+FH. This indicates that in a young population, inflammatory processes, rather than elevated low-density lipoprotein, account for a more rapid thickening of the intima-media space. FH alone was also associated with elevated CIMT but the FH mean was significantly lower than that for IRS. Low high-density lipoprotein was significantly related to elevated CIMT.