Objective: To investigate the association of MspI polymorphism of Cytochrome P4501A1 (CYP1A1) gene and smoking to the susceptibility to coronary artery disease (CAD).
Methods: The 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).
Results: The 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.
Conclusion: Both MspI polymorphism of CYP1A1 gene and smoking exposure promote the development of CAD.