The region most strongly associated with nicotine dependence in this study is represented by 14SNPs in a 40kb region on chromosome 8 (Table 2), with a single bin reaching genome-wide significance (p < 5 × 10−8). The most significant SNP is rs1451240 (OR=0.65,p = 2.4 × 10−8), and this SNP tags a bin on chromosome 8 including part of CHRNB3 in both African Americans and European Americans (supplemental Figures 2 & 3). Of interest, the SNP most strongly associated with nicotine dependence in previous studies, rs16969968in CHRNA5 on chromosome 15, had an odds ratio consistent with published studies (OR=1.31), but the p-value was not genome-wide significant (p=6.2 × 10−4). In contrast with the results from nicotine dependence, the GWAS using CPD as the dependent variable does not find any SNP to be significantly associated at a genome-wide level(Figure 1).
