Apolipoprotein E polymorphism in men and women from a Spanish population: allele frequencies and influence on plasma lipids and apolipoproteins

The apolipoprotein (apo)E phenotype and its influence on plasma lipid and a polipoprotein levels were determined in men and women from a working popula tion of Madrid, Spain. The relative frequencies of alleles epsilon 2, epsil on 3 and epsilon 4 for the study population (n = 614) were 0.080, 0.842 and 0.078, respectively. In men, apo E polymorphism was associated with variat ions in plasma triglyceride and very low-density lipoprotein (VLDL) lipid l evels. It was associated with the proportion of apo C-II in VLDL, and expla ined 5.5% of the variability in the latter parameter. In women apo E polymo rphism was associated with the concentrations of plasma cholesterol and low -density lipoprotein (LDL) and high-density lipoprotein (HDL) related varia bles. The allelic effects were examined taking allele epsilon 3 homozygosit y as reference. In men, allele epsilon 2 significantly increased VLDL trigl yceride and VLDL cholesterol concentrations, and this was accompanied by an increase of the apo C-II content in these particles. Allele epsilon 4 did not show any significant influence on men's lipoproteins. In women, allele epsilon 2 lowered LDL cholesterol and apo B levels, while allele epsilon 4 increased LDL cholesterol and decreased the concentrations of HDL cholester ol, HDL phospholipid and apo A-I. These effects were essentially maintained after excluding postmenopausal women and oral contraceptive users from the analysis. In conclusion: (1) the population of Madrid, similar to other Me diterranean populations, exhibits an underexpression of apo E4 compared to the average prevalence in Caucasians, (2) gender interacts with the effects of apo E polymorphism: in women, it influenced LDL and HDL levels, whereas in men it preferentially affected VLDL, and (3) allele epsilon 2 decreased LDL levels in women, while it increased both VLDL lipid levels and apo C-I I content iri men, but, in contrast to allele E4, it did not show an impact on HDL in either sex. (C) 1999 Elsevier Science Ireland Ltd. All rights re served.