Analysis of all phenotypes using SNP genotypes imputed using the 1000 Genomes Project revealed 20 additional associations below the suggestive genome-wide significance level (supplementary table 4). SNP rs9394152 in the 6p21 locus was the most significantly associated SNP with the age at smoking initiation (meta-analytic p=6.55×10−8) and, similarly to the majority of SNPs associated with this phenotype below suggestive genome-wide significance level, was characterized by high (≥0.96), cohort-specific imputation r2 coefficients (supplementary table 4). We observed novel associations of 3 SNPs with the lifetime average CPD; the most significantly associated SNP rs28675338 (r2=0.07 and D’=1.00 to rs1051730 according to 1000 Genomes Project Data) maps to the 15q25 locus. We also found one SNP associated with smoking cessation, with meta-analytic p<5×10−7 (supplementary table 4). Since cohort-specific, imputation r2 coefficients of the 4 SNPs, associated with lifetime average CPD and smoking cessation below suggestive genome-wide significance level, were rather modest (range 0.35–0.64; supplementary table 4), the observed associations certainly require additional confirmation and should be interpreted with caution. The three SNPs associated with current CPD with meta-analytic p<5×10−7 map to regions on
