We found nominally significant (P<0.05) allelic and genotypic association with smoking initiation of SNP rs2072660 and multilocus haplotypes (P<0.007-0.05) in CHRNB2 and nominal (P<0.05) allelic or genotypic association of SNPs in CHRNA7 (rs1909884), CHRNA9 (rs4861065) and CHRNB3 (rs9298629) with nicotine dependence.
For severity of nicotine dependence, two SNPs in CHRNA7 (rs1909884 and rs883473), one SNP in CHRNA5 (rs680244) and the interaction of a SNP in CHRNA7 (rs2337980) with neuroticism, were included in the model (P=2.24 x 10(-7), Nagelkerke r(2)=0.40).