Given that smoking ranks highly among public health problems in the world, public policy initiatives have been implemented to decrease smoking prevalence, while also emphasizing the negative health consequences of cigarette use. Examples of legal and regulatory policies related to tobacco include prohibition of smoking in public places and workplaces, restrictions on sale and marketing of tobacco products (especially to children), and federal legislation giving government agencies the authority to regulate tobacco (99). One study conducted in the Netherlands explored whether a change in environmental conditions – that is, smoking policies such as cigarette pack warnings about health consequences and bans on smoking advertisements – led to a change in the relative contribution of genetic factors to smoking initiation by comparing data on two cohorts of young adult twins. This study found that although the changes in policies and attitudes 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
