smoking cessation [Breslau and Peterson, 1996; Chen and Millar, 1998; Eisner et al., 2000; Lando et al., 1999]. Age of smoking onset in women is a significant predictor of cessation during pregnancy; a woman who initiates earlier is more likely to smoke while pregnant [Chen et al., 2006]. Individuals who initiate tobacco use early in life are also at greater risk for smoking-related lung cancer, in part because this tissue type continues to develop into early adulthood [Hirao et al., 2001; Wiencke and Kelsey, 2002; Wiencke et al., 1999]. In addition, smoking accelerates the rate of cervical maturation and cell proliferation, therefore resulting in an increased risk of cervical cancer [Hwang et al., 2009; Ma et al., 2011]. Given the long-term health implications of early tobacco use, many studies have worked to identify and understand the underlying genetic and environmental risk factors for early smoking behaviors.
