Analysis of candidate SNPs, with respect to the lifetime average CPD, revealed that the majority of those SNPs in the CHRNA3/CHRNA5 (15q25) and CYP2A6 (19q13) regions significantly associated with this trait showed the same direction of effect described previously.8–1126 However, SNPs from the 7p14, 8p11 (CHRNB3/CHRNA6 locus) and 10q23, as well as some SNPs from the CYP2A6 and CHRNA3/CHRNA5 loci, were not replicated in the current study with a nominal significance threshold. This may be caused by effect sizes that are too small to be detected in our populations or potentially to different genetic determinants of smoking behaviors within COPD subjects.
