The 19q13 MIR1323-MIR512-1-MIR512-2 noncoding RNA locus exceeded genome-wide significance in the age at initiation analysis (P=1.33E-06). Importantly, loci in the 19q13 region were previously implicated in quantity smoked by the TAG Consortium in their combined analysis and also by the ENGAGE11 analysis and, recently, by Loukola et al.41; the region has been proposed as a plausible candidate for further investigation in relation to smoking quantity given its role in nicotine metabolism (see e.g., 13). We now add age at initiation to the list of smoking phenotypes to be further investigated in relation to this biologically plausible region.
