Characterization of low-density lipoprotein subclasses in children.

Low-density lipoprotein (LDL) particles are heterogeneous in density, size, and chemical composition, and this heterogeneity is thought to be genetically influenced. In the present study, plasma LDL subclasses in 248 children aged 7 to 13 years were analyzed by gradient gel electrophoresis. The prevalence of small dense LDL (SDLDL), a potent atherogenic LDL, was 9.3%, which is lower than that reported in adults. Furthermore, children with this LDL subclass showed increased body fatness and dyslipidemia, including elevated plasma triglyceride and apolipoprotein (apo) B concentrations and decreased plasma high-density lipoprotein (HDL) cholesterol and apo A-I concentrations, compared with children without this phenotype. These findings suggest that in addition to genetic factors, environmental factors that affect these cardiovascular risk factors may also influence expression of the SDLDL subclass.