Influence of apolipoprotein E genotype on fat-soluble plasma antioxidants in Spanish children

Background: Apolipoprotein (apo) E is a major determinant of plasma lipid concentrations, which in turn influence the plasma concentrations of various fat-soluble vitamins. Objective: We aimed to analyze the effect of APOE genotype on fat-soluble antioxidant concentrations in children. Design: A total of 926 healthy boys and girls aged 6-8 y were selected from 4 cities in Spain. APOE genotyping was carried out, and plasma concentrations of lipids, apolipoproteins, and lipidsoluble antioxidants were measured. Results: Plasma lipid concentrations were strongly influenced by APOE genotype. The mean plasma concentration of a-tocopherol was 21.3 mu mol/L, which is one of the highest values ever reported for a population of children. Although plasma concentrations of alpha-tocopherol, gamma-tocopherol, lycopene, and a-carotene varied significantly between subjects with different APOE genotypes, most of these differences disappeared after adjustment for lipoprotein-related covariates. Nevertheless, tocopherol concentrations remained elevated in individuals with the E2/2 genotype. Multivariate regression analysis showed interactions of APOE genotype with triacylglycerol and apo B in determining a-tocopherol concentrations. When subjects were stratified according to major apo E groups, apo B appeared to be the most important predictor of alpha-tocopherol concentrations in all groups, whereas triacylglycerol was identified only in carriers of the E2 allele. Conclusions: The association between APOE genotype and lipophilic antioxidant concentrations is dependent mainly on the effect of the polymorphism on lipoprotein concentrations. However, triacylglycerol plays a role in determining the variability of a-tocopherol concentrations in E2 carriers only. This suggests that the alpha-tocopherol content in each lipoprotein class varies according to APOE genotype.