reporting the result for rs2072661. Irrespective of treatment, having the minor allele for rs2072661, which was present in 23% of our subjects, decreases the odds of quitting substantially (OR = 0.40; 95% CI 0.25–0.67, P = 0.0004). The interaction effect with treatment is not significant at an α = 0.05 level (P = 0.97); treatment OR for wild-type (WT) genotype = 1.77 (95% CI 1.02–3.07) and for minor allele OR = 1.81 (95% CI 0.79–4.14). At 6-months follow-up, the genetic effect for rs2072661 becomes more pronounced (OR = 0.31; 95% CI 0.18–0.55; P = 0.00006) and there is a more noticeable difference in the treatment effects by genotype, with treatment being substantially more effective for quitting the WT genotype group (OR = 2.14; 95% CI 1.20–3.81) when compared with the treatment effect within the individuals carrying the minor allele (OR = 0.83; 95% CI 0.32–2.19). A test for SNP-treatment interaction yields a P-value = 0.10. In addition to the two original SNPs within CHRNB2 showing an effect at EOT, there are three additional SNPs in LD with rs2072661 (rs1127314, rs2131902, and rs3766927) 3′ of the CHRNB2 gene with substantial genetic effects and significantly adjusted P-values from the LRT at 6-month
