['It has been reported that a common G-->A single nucleotide polymorphism (SNP) at the position -866 of the uncoupling protein-2 promoter (UCP2-866 G/A SNP) modulates UCP2 expression in adipose tissue and pancreatic beta-cell function, and lipid profiles. Reduced low density lipoprotein (LDL) particle size is a significant predictor of the development for coronary artery disease. The purpose of this study was to investigate whether the UCP2-866 G/A SNP was associated with serum LDL particle characteristics in a general Japanese population.', 'In 279 subjects (age 65+/-13 years), body mass index (BMI), percent body fat, blood pressure, and blood biochemical profiles were measured. The UCP2-866 G/A SNP was determined with a fluorescence-based allele-specific DNA primer assay system. LDL particle characteristics were analyzed by high-resolution polyacrylamide gel electrophoresis.', 'The frequency of the -866 A allele was 47.8%. There was no difference in triglyceride, total cholesterol, LDL-cholesterol, HDL-cholesterol, and small dense LDL levels between genotypes. However, subjects with the -866 A/A genotype had significantly lower mean LDL particle size levels (263.5+/-4.9 angstroms) than those with the -866 G/G genotype (264.6+/-4.9 angstroms, P=0.034). Multiple regression analysis revealed that the -866 A/A genotype was a significant variable contributing to the variance in the reduced LDL particle size levels (P=0.012).'] Is the UCP2-866 A/A genotype associated with low density lipoprotein particle sizes in the general population?