We suggest that further confirmation and resequencing studies of the four loci listed here are in order. Pancreatic cancer Supplementary material Supplementary Table 1 and Figure 1 can be found at Nicotine and Tobacco Research online (http://www.ntr.oxfordjournals.org/). Funding National Institutes of Health (DA015789) to Dr. Philibert. Declaration of Interests The authors do not have any conflicts with respect to this work. Dr. Philibert had full access to all data and calculations and takes full responsibility for the accuracy of the manuscript. Supplementary Material [Supplementary Material] Click here to view. [Article Summary] Click here to view. Acknowledgments The authors thank Laura Bierut and Scott Saccone for their complete and prompt provision of loci for genotyping, Steve Orzack for his edits to an earlier version of the manuscript, and the Rutgers Repository staff for all their help in making our studies possible.

Finally, the investigative team acknowledges a debt of gratitude to the late Remi Cadoret, the founder of the Iowa Adoption Studies who planned these studies jointly with Philibert, Todorov, Madden, and Heath.
To reduce smoking prevalence, we not only must provide treatment for smokers who are ready to quit but also must develop interventions that can enhance motivation for quitting and promote the use of effective cessation treatment programs. There is no single best strategy for motivating behavior change, but many leading health behavior change theories (e.g.

, the health belief model, health decision model, and protection motivation theory; Eraker, Kirscht, & Becker, 1984; Janz & Becker, 1984; Rogers, 1983) suggest that behavior change is induced in part by one’s perceived disease susceptibility and a desire to avoid disease (Weinstein, 1993). Thus, increasing one’s awareness of personal risk or harm caused by unhealthy habits could, theoretically, increase motivation for behavior change. Following this reasoning, many researchers have suggested that providing smokers with biologically based evidence (i.e., biomedical evidence) of smoking-related disease risk or physical impairment may be an effective way to motivate cessation (Lerman, Orleans, & Engstrom, 1993; Lerman et al., 1997; Marteau & Lerman, 2001; McClure, 2001). Whether this strategy works, however, is not clear.

Several literature reviews concluded that too few studies of acceptable methodological quality have been conducted to draw any firm conclusions (Bize, Burnand, Mueller, & Cornuz, 2007; McClure, 2001; Wilt, Niewoehner, Kane, MacDonald, & Joseph, 2007). Much of the literature reflects observational studies or randomized AV-951 experiments in which the intervention design confounded the risk assessment and provision or intensity of cessation counseling, thereby preventing examination of the independent effect of the biomedical risk assessment (Wilt et al.