In the current report, the strongest evidence for association with AOS was detected with SNP rs578776 (P = 0.004). There was also evidence for association between SNPs rs1948 (beta = 0.023, P = 0.018) and rs684513 (beta = 0.032, P = 0.017) and AOS. Similar to rs578776, the betas for these SNPs were positive, signifying that having more copies of the minor alleles is associated with a later age of smoking onset. Results with rs578776 and rs684513 are in agreement with a previous study [Broms et al., 2012], where there was evidence for association of age of onset of smoking (AOS) and the Locus 2 signal (rs578776) and rs684513. In addition, significance with rs1948 in this report is supported by previous findings of significant association with “smoking at age 14” and suggestive evidence with age of onset of smoking [Broms et al., 2012].
