Lung cancer is the leading cause of cancer death worldwide. Each year, >200,000 individuals are diagnosed with the disease in the U.S. alone (1
). Cigarette smoking is the leading cause of lung cancer, accounting for 87% of all cases. Although up to 70% of smokers say that they want to quit smoking, only a small proportion successfully do so. A number of cessation aids are available to help smokers quit, such as nicotine replacement therapy and telephone counseling, but relatively few smokers avail themselves of these services. Accordingly, increasing the uptake and use of effective smoking cessation services has been identified as a public health priority (2
The evidence to date suggests that biomarker risk assessments do not directly increase smoking cessation (4
). However, in previous studies, the incremental effects of biomarker risk feedback may have been diluted or ove-whelmed by the high intensity of the companion quit-smoking interventions [p155] (4
). Whether biomarker risk assessments might have intermediate beneficial effects, such as increasing uptake of subsequently offered effective quit-smoking interventions, is still an open question.
One type of biomarker risk assessment that is receiving increasing attention is genetic risk assessment. Genetic risk assessments or genetic test results might have particular beneficial potential when individuals are identified to be at increased risk (5
). For example, the gene that encodes for the enzyme glutathione S
) is deleted in up to 50% of the general population (6
). In meta-analyses, this common gene variant (called GSTM1
null or GSTM1
-missing) has been associated with increased lung cancer risk with a summary odds ratio for the association of GSTM1
null with lung cancer of 1.17 (95% confidence interval, 1.07-1.27; ref. 7
). Providing individuals with GSTM1
-missing test results might have beneficial effects related to smoking cessation.
A handful of studies have directly investigated the effects of such genetic susceptibility feedback on smokers' motivation and ability to quit smoking (8
). In addition, a few studies have used hypothetical genetic testing scenarios to achieve similar goals (17
). The studies to date have produced mixed results: some have found a modest motivational impact (9
), but others have found no impact (8
). In two randomized controlled trials (11
genetic risk feedback was offered as part of a complement of smoking cessation modalities of known efficacy, including brief in-person counseling, serialized telephone counseling, and/or nicotine replacement therapy. The trials found modest to no effects of specific genetic test results on cessation-related outcomes. However, smokers in these trials were offered genetic feedback within the context of a smoking cessation intervention: accordingly, those recruited were highly motivated to quit smoking. Under these conditions, genetic risk information may add little value to the efficacy of existing cessation interventions.
An alternative use of genetic risk information may be to engage smokers in intermediate behaviors as an initial step toward quitting, such as learning more about their personal smoking-related disease risk or increasing their interest in trying nicotine replacement therapy or telephone counseling. Conceptual models of information seeking (21
) suggest that genetic test results might engage smokers in a deeper processing of information about the health risks for smoking and, in turn, might increase interest in using smoking cessation services. Furthermore, offering genetic susceptibility testing at the time of a family member's diagnosis of cancer, a possible “teachable moment,” when the salience of smoking risks might be high, could motivate relatives who smoke to engage deeply with risk information and consider cessation services (22
). However, it is also possible that information at this time might not be considered thoroughly because it is too threatening (23
). Rather than smoking cessation itself, outcomes indicative of engagement with risk information, such as the rated quality of the information provided, accurate comprehension, and subsequent uptake of offered smoking cessation services, might therefore provide more appropriate indicators of beneficial effects of genetic risk feedback.
The present report examines how smokers processed and responded to personal genetic information about a common gene variant, GSTM1-missing, in the context of a blood relative's lung cancer diagnosis. Relative smokers were offered genetic testing and test results via Web-based information sessions. The Web-based approach increased reach and meant that “relative smokers” were able to access the information and their genetic test results, regardless of their geographic location. In addition, the Web-based format allowed unobtrusive evaluation of participants' engagement with the information immediately after test results were delivered, enabling examination of behavioral indicators of information processing. If found to be an effective and safe communication tool, this Web-based approach could in the future lend itself to integration with population-based smoking cessation interventions that are self-directed and portable.
In a previous report (24
), we compared the characteristics of relative smokers who did versus did not visit the Web site to consider genetic testing. Although the study was not designed to be nor communicated as being a smoking cessation intervention, relative smokers who logged on to the Web site were more motivated to quit smoking than those who did not log on. They also had greater previous awareness of genetic testing for cancer risk and were more frequent internet users (24
The present analyses focused on comprehension of test results and information processing among the relative smokers who requested genetic testing and received the test results. Based on previous research (23
) and stress and coping theories (25
), we anticipated that smokers receiving the “higher risk” result (GSTM1
-missing) might be less likely than those receiving the “lower risk” result (GSTM1
-present) to fully comprehend the meaning of the test result and more likely to reject their test results (e.g., report lower believability and perceived personal relevance) and to regret having taken the test. We also examined uptake of three types of offered smoking cessation services (e.g., printed and audio self-help materials, nicotine replacement therapy, serialized telephone counseling sessions). Based on information-seeking models (21
), we expected that smokers who received higher risk results might be more likely to request cessation services because of increased processing of personal risk results and related information. We also considered an alternative possibility based on stress and coping theory (25
) that smokers who received higher risk results might be less likely to take up smoking cessation services because of defensive processing of the personally threatening information. In addition, we explored the impact of test results on motivation to quit smoking and three behavior-related cognitions that have been found in previous research to mediate the relationships between persuasive communications and health behavior or behavior change outcomes: self-efficacy (confidence in ability to quit smoking), response efficacy (confidence that quitting smoking will reduce lung cancer risk), and perceived risk for lung cancer.