POLYMORPHISM OF THE APOLIPOPROTEIN-E GENE AND EARLY CAROTID ATHEROSCLEROSIS DEFINED BY ULTRASONOGRAPHY IN ASYMPTOMATIC ADULTS

Clinical and autoptical studies have suggested a predisposing role of the allele E4 of apolipoprotein E (apoE) in the development of atheros clerosis and cardiovascular disease. To investigate the possible contr ibution of apoE allele polymorphism to the carotid intima-media thickn ess (IMT) as assessed by ultrasound, we studied 260 asymptomatic nondi abetic subjects (121 men, 139 women; mean+/-SD age, 53+/-7 years), ran domly selected from the population register of the inhabitants of Trie ste, Italy. B-mode ultrasound was used to quantify the maximum IMT at 12 sites on the near and far wall of the common, bifurcation, and inte rnal carotid arteries. ApoE genotypes were determined from amplified a poE sequences by restriction isotyping. The frequencies of E2, E3, and E4 alleles were 0.073, 0.827, and 0.100, respectively. As expected, s ubjects with E4 allele had the highest levels of total serum cholester ol and LDL cholesterol, subjects with E2 allele had the lowest levels, and those with E3 genotype had intermediate levels. The echographic m easurements of carotid IMT showed increasing values from E2 to E4 carr iers. After adjustment for total and LDL cholesterol serum levels, tri glycerides, ratio of LDL to HDL cholesterol, age, sex, and body mass i ndex, ANCOVA showed that the common carotid IMT was significantly grea ter (P=.029) in subjects with E4 allele compared with E3 carriers. Our data confirm the influence of apoE4 on cholesterol levels and clearly show that apoE genotype affects carotid atherosclerosis in its early stages in middle-aged asymptomatic subjects.