In this study we extend these genetic findings to test GxE between the nicotinic receptor gene SNPs (rs16969968, rs578776, rs13277254, rs12466358) and retrospectively reported peer smoking during grades 9 −12 for nicotine dependence in the Collaborative Genetic Study of Nicotine Dependence (COGEND) sample of European Americans, which is composed of 1,054 current nicotine-dependent smokers as cases (FTND ≥ 4) and 984 smoking-exposed, but non-dependent, controls (smoked ≥ 100 cigarettes lifetime but lifetime FTND = 0). Given these case/control definitions, this study tests the interplay of genes and H.S. peer smoking on the transition from having been cigarette smoking exposed to nicotine dependence.
