OBJECTIVETo investigate the association of MspI polymorphism of Cytochrome P4501A1 (CYP1A1) gene and smoking to the susceptibility to coronary artery disease (CAD).

METHODSThe genotypes of CYP1A1 MspI site were detected using the methods of polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 349 cases with CAD and 404 non-CAD as controls. CAD diagnosis was confirmed by coronary angiograms. Genetic risk of CYP1A1 genotypes was analyzed by smoking index (SI).

RESULTSThe frequency of the predominant homozygotes TT, heterozygotes TC and the rare homozygotes CC in CAD group were not different with that of the controls (chi(2) = 3.224, P = 0.200). But in the smokers, the frequency of CC in CAD group was higher than that of non-CAD group (P = 0.002), while its odds ratio was 3.142 [95% confidence interval (CI) 1.481 - 6.668]. The odds ratio of genotype CC and heterozygote TC was 2.215 (95% CI 1.087 - 4.510) in the low dose cigarette smoking group, and was 1.407 (95% CI 0.709 - 2.791) in the high dose cigarette smoking group.

CONCLUSIONBoth MspI polymorphism of CYP1A1 gene and smoking exposure promote the development of CAD.