Quantitative effects of the apolipoprotein E polymorphism in a biracial sample of 9-10-year-old girls.

Genetic polymorphism at the apolipoprotein E locus (APOE) has been shown to have a significant impact on quantitative risk factors for coronary artery disease (CAD) in diverse populations. However, despite the recognition that atherosclerosis begins in childhood and that genetic factors are related to the initial stages of atherosclerosis, prior studies were carried out mostly on adults and little attention has been paid to genetic risk factors for CAD in children. We have examined the impact of APOE polymorphism on quantitative risk factors for CAD (apoAI, apoB, TC, LDL-C, HDL-C and TG) in a sample of 647 African American and 573 White 9-10-year-old girls who were enrolled in the National Heart, Lung and Blood Institute Growth and Healthy Study. The frequencies of the APOE*2, APOE*3 and APOE*4 alleles were 0.09, 0.76 and 0.15 in Whites and 0.11, 0.70 and 0.19 in African Americans, respectively. The APOE*2 allele was significantly associated with lower mean levels of LDL-C and apoB and the APOE*4 allele with higher levels of LDL-C and apoB in both racial groups. Variation in maturation stage, body fat and fat patterning, as assessed by skin fold measures and waist/hip ratio, accounted for a significant proportion of the variation in quantitative CAD risk factors.