The minor alleles of the other eleven SNPs with significant p-values in the CHRNA5-CHRNA3-CHRNB4 gene cluster were associated with decreased risk of heavy smoking (Table 2, highlighted by gray background). As with the risk SNPs, these protective SNPs share varying levels of LD (D' between 0.64 and 1.0, r2 between 0.39 and 0.98) and represent a single group of correlated SNPs. Although the LD across this region appears high when measured by D', the correlation between the risk and protective SNPS is low (r2≤0.2), indicating that they represent two unrelated associations (see Figure 1).
