Apolipoprotein E genotypes, circulating C-reactive protein and angiographic coronary artery disease: the Ludwigshafen Risk and Cardiovascular Health Study.

C-reactive protein (CRP) has been implicated in the development of atherosclerosis. The genetic polymorphism of apolipoprotein (apo) E is associated with the concentration of CRP. We analyzed the association between the apo E genotype, CRP and angiographic coronary artery disease (CAD). The concentration of CRP was similar in patients with stable CAD and in controls, but increased in patients presenting with acute coronary syndromes. In models adjusting for the main confounding variables, the alleles ɛ4 and ɛ2 were associated with decreased and increased concentrations of CRP, respectively, compared to the wild-type allele ɛ3. In spite of this, the ɛ2 allele was associated with a lower prevalence of angiographic CAD, while the slight over-representation of the ɛ4 allele was statistically not significant. We conclude that the apo E genotype is associated with circulating CRP. A causal role of CRP in the development of CAD would be supported if genotypes that raise CRP in the long-term were themselves associated with CAD. As we found the opposite, we suggest that the association between CRP and cardiovascular events reflects confounding and reverse causation.