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non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Genome-wide association studies (GWAS) have identified specific common genetic variants within a region on the long arm of chromosome 15 (15q25) as risk factors for lung cancer (1–3) and other smoking-related health outcomes, such as chronic obstruc-tive pulmonary disease (4,5), peripheral arterial disease (3,6), low birth weight in offspring (7), and lower body mass index (8). This region contains the a5, a3, and b4 nicotinic acetylcholine receptor subunit gene cluster, CHRNA5-CHRNA3-CHRNB4 (CHRNA5-A3-B4); although most studies to date have focused on the rs16969968 and rs1051730 single-nucleotide polymorphisms (SNPs) within this gene cluster, there is emerging evidence that other SNPs within this region are also associated with smoking behavior (9). A few studies have suggested that rs16969968 and rs1051730 SNPs do not relate to smoking history (2,10), but mos