These results are beginning to fill gaps in our understanding of the joint association of specific genes and environmental risk factors with nicotine dependence. The presence of an interaction between identified risk genes and environmental factors suggests that environmental risk factors may accentuate the effect of specific risk genes for nicotine dependence. Identification of environmental factors that might modify the expression of specific risk genes will allow for the development of more effective interventions. These analyses lay the ground work for future prospective studies.
