towards smoking led to a decrease in the prevalence of smoking, it did not change the heritability of smoking. These findings did not provide support for GxE between initiation and public policy initiatives (100). Meanwhile, a few studies demonstrate interactions between policy initiatives and the heritability of daily and regular smoking have found evidence for GxE (96,101,102), suggesting that historical time periods can be characterized as distinct social environments that moderate the contribution of genes to cigarette use (103). One study using twin pairs from the National Survey of Midlife Development in the United States found that the timing of the first Surgeon General’s Report coincides with an increase in the genetic influences on regular smoking, but subsequent legislation prohibiting smoking in public places reduced these influences (101). Another study conducted using data from the National Longitudinal Study of Adolescent Health, investigated interactions between state-level measures characterizing social and institutional effects on smoking and daily smoking and smoking onset of adolescents. At the state level, the effect of genes on daily smoking were lower in states with relatively high taxes on cigarettes and greater controls on vending machine and cigarette advertising, while there was no variation in heritability estimates for
