The effect of SNPs on cotinine levels and CPD were investigated among current smokers only (n=935). We did not observe a significant association of any of the investigated SNPs with CPD (Table 3). In contrast, increased cotinine levels were associated with the minor alleles of rs578776 and rs16969968 on 15q25 (Ptrend=0.03, and Ptrend=0.001, respectively), as well as rs4105144 and rs7937 on 19q13 (Ptrend=0.0001, and Ptrend=0.003, respectively, Table 3). The direction of effects of 15q25 variants on circulating cotinine levels were consistent with that expected based on previously published results for CPD (Table 2). In contrast, the 19q13 variants showed opposite effects on circulating cotinine level compared to those reported for CPD previously (Table 2). No other SNPs were significantly associated with cotinine levels.
