APOLIPOPROTEIN-E PHENOTYPES AND SERUM-LIPIDS IN NEWBORNS AND 3-YEAR-OLD CHILDREN - THE CARDIOVASCULAR RISK IN YOUNG FINNS STUDY

Background. Apolipoprotein E (apoE) phenotype is a genetic determinant of plasma total cholesterol and low density lipoprotein (LDL) cholest erol concentrations, that are classical coronary heart disease risk fa ctors. ApoE appears in three major isoforms E2, E3, and E4, coded by c orresponding alleles epsilon 2, epsilon 3, and epsilon 4. These give r ise to six different phenotypes. Objective. To study the associations of apoE phenotype with cord serum lipids (during minimal enteral nutri tion), and with serum lipids of 3-year-old children. Subjects and meth ods. We determined serum lipid levels and apoE phenotypes in 206 newbo rns and 259 3-year-old children in connection with a larger follow-up study of atherosclerosis precursors in children and young adults. ApoE phenotyping was done directly from plasma by isoelectric focusing fol lowed by immunoblotting. Results. The effect of apoE phenotype on seru m total and LDL cholesterol was significantly different in newborns an d 3-year-old children (two-way ANOVA, interaction between apoE phenoty pe and age group: P < .001 for both). In 3-year-old children, the conc entrations of serum total cholesterol and LDL cholesterol increased wi th apoE phenotype in the order of E3/2, E3/3, E4/3, and E4/4, in both males and females (P < .0001). On the contrary, in neonates total chol esterol and LDL cholesterol concentrations were low and did not differ significantly between apoE phenotypes (P > .05) either in males or in females. The mean serum levels of triglycerides and high density lipo protein cholesterol did not differ between apoE phenotypes either in 3 -year-old children or newborns. Conclusions. The results show that the differences in serum total and LDL cholesterol levels between apoE ph enotypes are formed after birth by the influence of environmental fact ors and suggest that both genetic and external factors influence the l evels of serum cholesterol concentrations during the first years of li fe.