title: Apolipoprotein E polymorphism has no independent effect on plasma levels of lipoprotein(a).
abstract: Previous studies show conflicting results concerning an influence of apolipoprotein E (apo E) phenotype on lipoprotein(a) (Lp(a)) plasma levels. We speculated that it is not the apo E phenotype itself but rather its effect on plasma lipid concentrations that might influence Lp(a) levels. In 1562 subjects concentrations of triglycerides, LDL-cholesterol and Lp(a) were measured by standard laboratory methods. Apo(a) and apo E isoforms were determined by sodium dodecyl sulfate gel electrophoresis and isoelectric focusing, respectively, followed by immunoblotting. An univariate analysis revealed a significant influence of apo(a) isoforms, apo E phenotype, triglycerides and LDL-cholesterol on Lp(a) plasma levels (ANOVA: P < 0.001, P < 0.02, P < 0.001 and P < 0.001, respectively). In a multivariate analysis, however, the influence of the apo E phenotype was no longer significant (P>0.10), whereas apo(a) isoforms, LDL-cholesterol quintiles and triglyceride quintiles explained 29.2, 2.8 and 1.0% of the variation of the Lp(a) levels (for all three variables: P < 0.001). We conclude that apo E polymorphism does not exert an independent effect on Lp(a) concentrations. Any influence is mediated through the effect of apo E polymorphism on plasma lipids.
authors.affiliation: Medical Department II, Klinikum Grosshadern, University of Munich, Germany.
authors.forename: M M
authors.initials: MM
authors.lastname: Ritter
authors.forename: J
authors.initials: J
authors.lastname: Gewitsch
authors.forename: W O
authors.initials: WO
authors.lastname: Richter
authors.forename: H C
authors.initials: HC
authors.lastname: Geiss
authors.forename: M W
authors.initials: MW
authors.lastname: Wildner
authors.forename: P
authors.initials: P
authors.lastname: Schwandt
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001057:Apolipoproteins E / Q000097:blood / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D008078:Cholesterol, LDL / Q000097:blood; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood / Q000235:genetics; D015151:Immunoblotting; D017270:Lipoprotein(a) / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011110:Polymorphism, Genetic / Q000235:genetics*; D012189:Retrospective Studies; D014280:Triglycerides / Q000097:blood
chemical_list: D001057:Apolipoproteins E; D008078:Cholesterol, LDL; D017270:Lipoprotein(a); D014280:Triglycerides