The strongest genetic association finding for smoking, the rs16969968 variant in the α5 nicotinic receptor subunit that causes an amino acid change, is a rare variant in populations of African and Asian descent [15]. Two recent genetic studies of African Americans, one examining nicotine dependence and the other lung cancer, implicated the chromosome 15 region as associated with disease even though the risk allele was rare, which adds further support to the hypothesis that this region contributes to both smoking and lung cancer [27-28]. This chromosome 15 region was also identified in a Chinese population though a different group of correlated variants was reported [29]. Additional genetic studies of individuals of non-European descent will be important to narrow down the search for biologically causal genetic variants that explains the statistical evidence for disease associations. We await these future studies.
