In this first study of the interplay between specific genes and H.S. peer smoking we found both independent and interaction effects with SNPs in the nicotine receptor genes: rs16969968 and rs578776 in the CHRNA5-CHRNA3-CHRNB4 gene cluster, rs13277254 tagging CHRNB3-CHRNA6 and rs12466358 in the CHRND gene. Number of H.S. peers who smoked had little effect on the probability of nicotine dependence among those with the high risk AA genotype at the functional SNP rs16969968 but had substantial effects among those with lower risk genotypes. This result suggests that those with the AA genotype at rs16969968 may not need as supportive a social environment to make the transition from having initiated smoking to becoming nicotine dependent smokers as those with lower risk genotypes.
