State-Level Moderation of Genetic Tendencies to Smoke

Objectives. I examined genetic influences on smoking among adolescents and differences in the heritability of smoking across states in the United States. Methods. With data from the National Longitudinal Study of Adolescent Health (participants aged 12-21 years), I used a multilevel twin- and sibling-pair (N=2060 pairs) regression model. Results. Daily smoking (hereditability estimate [h(2)] =0.54) and smoking onset (h(2) =0.42) were both highly heritable. Whereas the genetic influences on smoking onset were consistent across states, there was significant variation in these influences on daily smoking. Genetic influences on daily smoking were lower in states with relatively high taxes on cigarettes and in those with greater controls on the vending machines and cigarette advertising. Genetic influences were also negatively associated with rates of smoking among youths. Conclusions. At the state level, gene-environment interaction models are best characterized by the model of social control. State policies may influence genetic tendencies to smoke regularly, but they have not affected the genetic contributions to cigarette onset or experimentation. Future tobacco-control policies may emphasize the heritable endophenotypes that increase the likelihood that adolescents will initiate smoking. (Am J Public Health. 2009;99:480-486. doi: 10.2105/AJPH.2008.134932)