Genetic Testing for Smoking Cessation
Smokers' ability to quit smoking may be influenced by genetic variation. The use of genetic testing may hence increase cessation rates.
More than 1.2 billion smokers exist worldwide, and tobacco smoking continues to be the largest preventable cause of disease and premature death. With smoking it is true that cessation reverses most of its adverse effects. Although many pharmacological therapies are available, even then the cessation rate remains low as 15% to 30% which gives way to genetically tailored therapies like nicotine dependence tests. Inherited or genetic differences in nicotine clearance rates are associated with smoking behavior and cessation rates, with a genetically-informed biomarker, the nicotine metabolite ratio, NMR.
In a cross sectional survey conducted in Netherlands, the knowledge of smokers, their attitudes, preferences and intention to undergo genetic testing were assessed using an online cross-sectional survey. Total of 587 participants were selected from the database of an internet research company.
They were queried with their smoking characteristics like type of tobacco product, number of cigarettes and/or shags per day, level of nicotine dependence (assessed by the Fagerström Test for Nicotine Dependence. Their knowledge of influence of genetics on nicotine dependence and regarding the influence of genetics on smoking cessation (treatment) were assessed.
While 88.9% knew that it is important to quit, about half (49.1%) of the respondents knew that less than half of the smokers who want to quit succeed. As far as knowledge was concerned most of the Dutch population did not know about the genetic influences on smoking predisposition. About one-third knew that the chance to become addicted to smoking is influenced by genes (29.5%) and that genes exist that increase the chance of becoming addicted to smoking. only 36% believed that genetic predisposition is an (very) important cause of smoking.
Instead of being relieved by genetic tests most participants were worried that the results would become known at work or to the employer and that they would not be able to tell others. Participants were least convinced that they would be relieved by the results and most convinced that a genetic test would give a reliable result about the presence of a genetic predisposition to become addicted to smoking, and that it could help to determine the correct dose of smoking cessation medication.
While most participants (73.6%) would prefer to receive more information as well as get the genetic tests done from their General practitioners, they indicated not to be willing to pay >€50 for the genetic test. A low number of participants (16.6%) were (completely) interested in undergoing a genetic test and half of them (50.6%) would not ask their GP for the test.
Knowledge level of participants on the influence of genetic factors on smoking addiction and cessation, and even on basic mechanisms of heredity, is highly inadequate and needs attention. Increasing awareness of the probability and consequences of having a genetic predisposition, and advantages and disadvantages for genetic testing, might also be an effective strategy to motivate smokers to undergo a genetic test for smoking cessation. Therefore it seems likely that General Practitioners will play an important role in the counseling of patients about undergoing genetic testing.
Further, patients' awareness of such a test can also be increased by addressing via other channels of communication, for instance, information leaflets or information campaigns on TV, radio or in magazines or newspapers. Thus when they have some knowledge about the influence of genetic factors on smoking and smoking cessation they would prefer and look for these tests.
This study suffered from few limitations as the field of pharmacogenetic influences on smoking cessation is still in its infancy, and therefore, no well-accepted tests to tailor smoking cessation treatment are commonly available. The smokers may not be familiar with genetic testing for smoking addiction and genetically tailored cessation treatments or even genetics in general, it is questionable whether they were able to give a well-considered answer to all the questions they were asked. Lastly, that the participants were recruited via an internet research company, selection bias might have occurred due to the non-representative nature of the internet population and the self-selection of participants.
Therefore we conclude that strategies for counselling patients and communicating their test results have to be adopted by general practitioners in a way to remove misconceptions regarding smoking cessation rates.
Reference: Knowledge, attitudes and preferences regarding genetic testing for smoking cessation. A cross-sectional survey among Dutch smokers; Marieke Quaak et al; BMJ 2011
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