Low-density lipoprotein particle size and its regulatory factors in school children.

Small low-density lipoprotein (LDL) particles are more atherogenic than larger LDL particles. To help prevent atherosclerotic coronary heart diseases, it may be useful to understand risk factors during childhood. In the present study, we evaluated LDL size and its relationship to other risk factors for atherosclerotic coronary heart disease. LDL size was measured by 2-15% gradient gel electrophoresis in 586 Japanese children (316 boys and 270 girls). Plasma lipids, apolipoproteins (apo), glucose, and insulin were also determined by conventional methods. Pattern B (LDL size < 25.5 nm) was found in 10.8% of boys and 4.4% of girls. Children with pattern B had a higher body mass index (BMI) and insulin resistance and a more atherogenic lipoprotein profile [higher triglycerides, higher apoB, and lower high-density lipoprotein cholesterol (HDL-C)] than children with pattern A (LDL size > or = 25.5 nm). BMI, insulin resistance, and plasma concentrations of triglycerides, glucose, and insulin decreased and plasma concentrations of HDL-C and apoA-I increased as LDL size increased. HDL-C and insulin in boys, and BMI, HDL-C, and apoA-I in girls predicted 22.9 and 28.1% of the variability of LDL size, respectively. LDL size was correlated with BMI and plasma concentrations of HDL-C, apoA-I, and insulin. Although the contribution of these parameters to LDL size in children was less than that in adults, improvement of these parameters by changes in lifestyle might be important for preventing the development of atherosclerosis even in children.