When we investigated the association between APOE genotype status and CHD regardless of smoking status, we found strong evidence for a linear association between APOE genotype and CHD status when individuals were arranged in the following order: ε2/ε2, ε2/ε3, ε3/ε3, ε3/ε4 or ε4/ε4 with the log odds of CHD increasing by 0.046 (SE 0.019; P = 0.017) for each incremental increase in APOE genotype status (Fig. 3). This evidence concerns the gene APOE and coronary artery disorder.