Apolipoproteins E and C-III in apo B- and non-apo B-containing lipoproteins in middle-aged women from the Stanislas cohort: effect of oral contraceptive use and common apolipoprotein E polymorphism

Oral contraceptive (OC) use and common apo E polymorphism are well known to modify serum lipid and lipoprotein concentrations. The combined effect of OC use and apo E genotype on the concentration of apo E or apo C-III in apo B- (apo E-LpB or apo C-III-LpB) or in non-ape B-containing lipoparticles ( apo E-Lp-non-B or apo C-III-Lp-non-B) are unknown. Our study comprised 613 women, aged 30-45 years, genotyped for common apo E polymorphism and who di ffered in their combined low-dose OC consumption. The concentrations of apo C-III. apo C-III-LpB and apo C-III-Lp-non-B were significantly higher in O C users than in non-users by 13. 23 and 8%, respectively, without significa nt interaction with the apo E genotype. The concentrations of apo E and apo E-Lp-non-B were significantly lower (differences bring - 14% and - 31% res pectively) in OC users than in controls whereas the apo E-LpB concentration was significantly higher ( + 19%), resulting in a redistribution of apo E from Lp-non-B towards LpB. Total apo E and apo E-Lp-non-B concentrations we re higher in subjects carrying the epsilon2 allele and lower in those with the epsilon4 allele epsilon3/epsilon3 compared to epsilon3/epsilon3 subject s (P < 0.001). The opposite held for the apo E- LpB concentration (P < 0.05 ). The main finding is the significant interaction between apo E genotype a nd OC use (P < 0.01) on apo E-Lp-non-B concentration, the <epsilon>4 carrie rs showing the smallest differences between OC users and non-users in compa rison with the epsilon2 Or epsilon3/epsilon3 carriers. These results sugges t that the common apo E polymorphism can modulate the OC use effect. (C) 20 01 Elsevier Science Ireland Ltd. All rights reserved.