In summary, the incorporation of AOS into genetic models of nicotine dependence seems to be a promising avenue to discover novel SNPs that may be important in the context of different environments. The age at which a person begins smoking is a complex phenomenon that is correlated with a number of behaviors, and so it would be naive to treat AOS as a simple environmental exposure in interpreting these findings. Nonetheless, it seems reasonable to pursue some of the present findings in replication attempts, and to extend this approach to genome-wide association studies.
