Lipoprotein-subclass particle numbers in children with abdominal obesity.

Background: The lipoprotein particle number (PN) profile may be a better marker of cardiovascular risks than standard serum lipid measurements. The aim of this study was to analyze the lipoprotein PNs in Japanese children with abdominal obesity and to determine the subclass profile.

Methods: The participants included 164 Japanese children (79 boys and 85 girls) aged 9-13 years. We obtained waist-to-height ratios (WHtR) and serum lipids for all participants. The lipoprotein PNs in 12 subclasses were analyzed using high performance liquid chromatography (HPLC).

Results: Both boys and girls with abdominal obesity (WHtR ≧ 0.5) had significantly higher triglyceride (TG), very-low-density lipoprotein (VLDL)-PN, and all VLDL-subclass PNs compared to those without abdominal obesity. In boys with abdominal obesity, low-density lipoprotein (LDL)-PN was higher, but lipoprotein cholesterol (LDL-C) was not, and high-density lipoprotein cholesterol (HDL-C) was lower, but HDL-PN was not compared to those without abdominal obesity. In girls with abdominal obesity, LDL-C and LDL-PN were not significantly different and both HDL-C and HDL-PN were lower compared to those without abdominal obesity. Subclass analyses demonstrated that boys and girls with abdominal obesity had significantly lower very large and large HDL-PNs than those without abdominal obesity. In addition, medium, small, and very small LDL-PNs were higher in boys with abdominal obesity than those without abdominal obesity.

Conclusions: This study found that Japanese children with abdominal obesity are affected by the lipoprotein-subclass PN profile, with sex differences in the LDL- and HDL-subclasses, which is different from results obtained by standard serum lipid measurements.