Tobacco smoking is a serious public health problem associated with significant morbidity and mortality (1). The prevalence of current smoking in US adults remains high: 20.8% in 2006 (2). Adolescents continue to initiate smoking (3–5), and many who smoke become dependent (6). Increasing our understanding of the etiology of nicotine dependence is critical for identifying new opportunities for interventions to prevent development of nicotine dependence and treatments to improve cessation rates. It has been understood for some time that both genes and environmental factors influence the development of nicotine dependence (7–10). However, the synthesis of specific genetic and environmental risks for nicotine dependence is just beginning (11, 12). In this study, we examine whether level of parent monitoring modifies the risk of nicotine dependence associated with two genetic variants in the nicotinic receptor genes CHRNA5(rs16969968) and CHRNA3(rs3743078).
