Genetics strongly determines the wall thickness of the left and right carotid arteries

In 76 supposedly healthy families, we investigated the familial resemblance of left and right carotid intima-media thickness (IMT) measured by B-mode ultrasonography and the impact of the common apolipoprotein E (apo E) polymorphism and the insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE). Genetic factors accounted for about 30% of IMT variation. The insertion/deletion ACE polymorphism did not influence carotid IMT, whereas apoE polymorphism explained about 1.5% of only right carotid IMT variability independently of cholesterol levels. The apo epsilon 2 and apo epsilon 4 alleles were associated with lower right carotid IMT than was the apo epsilon 3 allele. We conclude that genetic factors strongly contribute to IMT variability in healthy people and that the apo E polymorphism may be one of these factors.