ApoE polymorphism in a small Mediterranean island: Relationships with plasma lipids, lipoproteins and LDL particle size

Polymorphisms of apoE gene are able to modulate lipoprotein metabolism at different steps and to influence LDL-cholesterol (LDL-C) levels and also other lipoproteins features. Population studies documented large differences in the frequency of apoE alleles which could be even related to the prevalence of cardiovascular disease. In this study we evaluated the apoE genotypes and allele frequency in 576 subjects living in a small island in the Tyrrhenian Sea and the relative contribution of apoE polymorphism on plasma lipid and lipoprotein profile, including LDL particle size. We found a cumulative frequency of 0.073, 0.866 and 0.061 for ε2, ε3 and ε4 alleles respectively. Moreover ε3 subjects had only triglyceride levels significantly lower and LDL-C and lipoprotein (a) (Lp(a)) levels higher than ε2 carriers. LDL-particle size was significant smaller in ε2 subjects than both ε3 and ε4 carriers, but the difference disappeared when data were adjusted for triglycerides. In conclusion we have provided further evidence of a low prevalence of ε4 allele in a Mediterranean population which may represent a genetic protective factor of these populations. Environmental factors, such as diet, occurring in this area may have attenuated the influence of this gene on plasma lipoproteins.