been observed between aggregated, latent genetic and environmental influences on cigarette smoking using the genetically informative twin-family design. Twin studies have demonstrated that the genetic risk for adolescent smoking is higher in urban than rural communities.36, 37 The authors posited that urban communities were characterized by decreased community monitoring that allowed for the greater expression of genetic predispositions for adolescent substance use.36, 38 Taken together, this literature suggests that riskier environments (for example, increased stressful life events and fewer social constraints) enable predispositions towards substance use to be manifested.39 Despite this growing GxE literature, few studies have examined the role of gene–environment interactions in African American populations. In addition, previous GxE studies have primarily focused on individual-level factors (the experience of sexual abuse), whereas macro level influences, such as the social environment (neighborhood characteristics) have also been demonstrated to influence smoking behaviors,10, 38 and may also moderate genetic influences on smoking.
