Interestingly, adjusting for CPD had little influence on the association between the CHRNA5-A3-B4 gene variants and abstinence in our study and in a number of previous studies which evaluated the association between CHRNA5-A3-B4 gene variants and smoking abstinence (15, 20). This suggests that the influence of CHRNA5-A3-B4 gene variants on smoking abstinence is not related to their modest effect size on altering tobacco consumption. In addition, the impact of rs2036527 remained unaltered when we controlled for CYP2A6 and/or CYP2B6 genotype, suggesting the impact of rs2036527 on cessation was independent of variation in nicotine or bupropion metabolism.
