Nineteen SNPs on chromosome 15 in the region that encompasses the CHRNA5-CHRNA3-CHRNB4 gene cluster were strongly associated with heavy smoking (Table 2 and Figure 1). All of these associations were highly statistically significant, even after conservative Bonferroni correction for multiple comparisons (p-values ranged 0.019-2.8E-07 after correction). In addition, all the associations remained significant for both men and women when gender-specific analyses were done (data not shown). These findings replicated the association for nine of the SNPs that had been identified by a GWAS (7) and parallel candidate gene study (8) of nicotine dependence and identified ten new associated SNPs in the same region.
