Objective: Large waist circumference (WC) is associated with cardiovascular disease and type 2 diabetes. The present study determined differences in lipoprotein particle size and subclass concentration and markers of vascular smooth muscle function in children using WC percentile cutoffs.

Research Design and Methods: Participants were 182 children (87 black, 92 female) aged 8–<18 yr. Each participant had a measurement of WC and a fasting blood draw for the measurement of lipoprotein particle concentration and size and circulating biomarkers of endothelial function. Participants were divided into age-, sex-, and ethnicity-specific WC percentiles of below 75th, 75th to 90th, and at least 90th percentiles, and differences in lipoproteins and vascular smooth muscle markers were compared among groups.

Results: Children in the 90th percentile or higher for WC had significantly smaller low-density lipoprotein and high-density lipoprotein size than children with WC below this percentile. For lipoprotein concentration, small low-density lipoprotein and large very low density lipoprotein and chylomicrons were lower, and large high density lipoprotein concentrations were higher in children whose WC was below the 75th percentile compared with those with WC in the 90th percentile or higher. Concentrations of the vascular smooth muscle biomarkers, intercellular adhesion molecule-1, and E-selectin were significantly higher in children with WC in the 90th percentile or higher than in children below the 75th percentile.

Conclusion: Youths with WC in the 90th percentile or higher have an atherogenic lipoprotein profile with increased concentrations of biomarkers of vascular smooth muscle dysfunction. Given that atherosclerosis begins in childhood, such evidence suggests that these children should be targeted for interventions to reduce adiposity at an early age.