To compare the association signals detected by this study with those detected in other populations from previous studies, we have summarized both individual SNP and haplotype results in Figures 2 and 3, respectively. To our knowledge, approximately 25 SNPs in this region are reported to be associated with smoking-related and LC phenotypes. Among the 7 SNPs found to be nominally associated with SI, SQ, and SC, rs6495308 in CHRNA3 was also found associated with CPD in two European American samples [24]. All the remaining 6 SNPs (1 in CHRNA5, 1 in CHRNB4, and 4 in the intergenic regions) were unique to this Korean sample. It would be of great interest to individually genotype additional SNPs in this region in the sample, especially rs1051730 and rs16969968, which showed unequivocally significant association signals with SQ or CPD in several previous studies [15], [54], [55]. Recently, Le Marchand et al. [56] used urinary biomarkers to test whether rs1051730 and rs16969968 are associated with a higher level of nicotine and exposure to tobacco-specific carcinogenic substances per cigarette dose in a Hawaii study of 583
