reducing excess health-care utilization and improved labor supply on a larger scale (4). However, to improve strategies for disease prevention and intervention efforts focused on smoking cessation, a better understanding of genetic, social environment, and individual determinants of risk contributing to cigarette use are needed. In other words, we need to be able to disentangle the etiology of cigarette use and identify the conditions under which genes, the environment, and their interaction impact cigarette use behaviors. Through this narrative review, we seek to integrate twin and molecular genetic studies of GxE in cigarette use. Specifically, this narrative review provides a brief overview of studies investigating genetic and environmental factors influencing cigarette use separately, and then summarizes gene-environment interactions in cigarette use behaviors.
