In this study, we investigated the association of SNPs in the CHRNA5-CHRNA3-CHRNB4 gene cluster with heavy smoking using participants in the American Cancer Society Cancer Prevention Study II (CPS-II) Nutrition Cohort (14). Smoking intensity and duration information collected at three time points over 15 years was used to identify 1,452 heavy smokers and 1,395 light smokers for this study. The association of the CHRNA5-CHRNA3-CHRNB4 gene cluster with heavy smoking was explored by genotyping 17 SNPs spanning over 200 kb of chromosome 15 that include these genes. In addition, the association of common SNPs in other nicotinic receptor genes, specifically in the CHRNB3-CHRNA6 gene region, and the CHRNA4 and CHRNB2 genes, was investigated to determine the importance of these genes in heavy smoking.
