Associations of cytochrome P450 oxidoreductase genetic polymorphisms with smoking cessation in a Chinese population.

Recently, a single nucleotide polymorphism (SNP) A503V (rs1057868) in cytochrome P450 oxidoreductase (POR) gene was reported to influence nicotine metabolism. Considering the importance of nicotine metabolism to smoking cessation, the aim of this study was to investigate the association between POR gene polymorphisms and smoking cessation in a Chinese population. A case-control study was conducted with 363 successful smoking quitters as the cases, and 345 failed smoking quitters as the controls. Eight tagSNPs which cover the entire gene and four functional SNPs were selected and genotyped. Logistic regression was used to explore the relationship between POR SNPs and smoking cessation in codominant, additive, dominant and recessive models. After adjustment for potential confounders, multiple logistic regression analysis indicated that POR rs3823884 and rs3898649 were associated with increased possibility of smoking cessation. Meanwhile, POR rs17685 and rs239953 were shown to have negative effect on successful smoking cessation. No significant differences in the distribution of haplotypes between cases and controls were detected. In conclusion, this study reveals that four SNPs in the POR gene (rs3823884, rs3898649, rs239953 and rs17685) may affect the susceptibility of smoking cessation in a Chinese Han population.