Associations of individual SNPs with the three phenotypes were determined with the PLINK program [29], and the results are shown in Table 2. Altogether, we found 7 SNPs that had nominally significant associations with at least one smoking-related phenotype in either the total or the male sample. In the total sample, we found that the A allele of rs951266 in CHRNA5 was nominally significantly associated with SI (P = 0.023; odds ratio [OR] = 1.32; 95% confidence interval [CI]: = 1.04, 1.67) and SQ (P = 0.008; OR = 1.48; 95% CI: 1.11, 1.98), and the G allele of rs11072768 in CHRNB4 was nominally significantly associated with SI (P = 0.015; OR = 1.14; 95% CI: 1.03, 1.27), SQ (P = 0.028; OR = 1.17; 95% CI: 1.02, 1.34), and SC (P = 0.018; OR = 1.16; 95% CI: 1.03, 1.31). Furthermore, the associations of SNPs rs8043123 (C), rs4887077 (T), and rs11638372 (T) with SQ and the association of rs2869550 (C) with SC reached nominal significance.
