The genotype associations for the risk SNPs in the CHRNA5-CHRNA3-CHRNB4 gene cluster show a dose response [Table 3, for rs16969968, GA OR=1.45 (95% CI: 1.24, 1.70), AA OR=1.77 (95% CI: 1.37, 2.29)]. The same is true for the protective SNPs [Table 3, for rs3743078, CG OR=0.68 (95% CI: 0.58, 0.80), GG OR=0.49 95% CI: 0.34, 0.68)]. The highly significant p-trends for these results support both sets of variants following an additive genetic model. All the findings in Table 3 remain statistically significant after correction for multiple comparisons except for the results for rs1996371.
