Multiple genetic tests for susceptibility to smoking do not outperform simple family history

How has the brain disease model of addiction contributed to tobacco control?

Our paper evaluates the extent to which the brain disease model of addiction (BDMA) has contributed to reducing the prevalence of tobacco smoking and  tobacco-related harm over the past 20 years. We discuss the ways in which genetic and neuroscience research on nicotine addiction have contributed to our understanding of tobacco smoking. We then examine the extent to which the BDMA has produced more effective treatments to assist smoking cessation. We also assess the degree to which the BDMA has contributed to the tobacco control policies that have produced substantial reductions in tobacco-related morbidity and mortality in the two decades since the model was first proposed by Alan Leshner. We also assess whether the BDMA has reduced the stigmatisation of people who smoke tobacco.

Unwarranted optimism in media portrayals of genetic research on addiction overshadows critical ethical and social concerns

The cost of addiction in the United States, in combination with a host of new tools and techniques, has fueled an explosion of genetic research on addiction. Because the media has the capacity to reflect and influence public perception, there is a need to examine how treatments and preventive approaches projected to emerge from addiction genetic research are presented to the public. The authors conducted a textual analysis of 145 news articles reporting on genetic research on addiction from popular print media in the United States and from popular news and medical internet sites. In articles that report on prevention, the media emphasize vaccine development and identifying individuals at genetic risk through population screening. Articles that emphasize treatment often promote current pharmaceutical solutions and highlight the possibility of tailoring treatments to specific genetic variants. The authors raise concerns about the tendency of this coverage to focus on the benefits of pharmaceutical treatments and genetic-based approaches to prevention while neglecting or downplaying potential risks and ethical issues. This analysis suggests a need for more balanced, evidence-based media reporting on the potential outcomes of genetic research.

The brain disease model of addiction: is it supported by the evidence and has it delivered on its promises?

Since 1997 the US National Institute on Drug Abuse has advocated a brain disease model of addiction (BDMA). We assess the strength of evidence for the BDMA in animals, neuroimaging studies of people with addiction, and current research on the role of genetics in addiction. We critically assess claims about the medical and social benefits of use of the BDMA because the social implications are often implied as a reason to accept this model. Furthermore, we argue that the BDMA is not supported by animal and neuroimaging evidence to the extent its advocates suggest; it has not helped to deliver more effective treatments for addiction; and its effect on public policies toward drugs and people with addiction has been modest. The focus of the BDMA is on disordered neurobiology in a minority of severely addicted individuals, which undermines the implementation of effective and cost-effective policies at the population level to discourage people from smoking tobacco and drinking heavily. The pursuit of high technology direct brain interventions to cure addiction when most individuals with addiction do not have access to effective psychosocial and drug treatments is questionable.

Non-cigarette tobacco and the lung

Cigarette smoking is known to cause a wide range of damaging health outcomes; however, the effects of non-cigarette tobacco products are either unknown or perceived as less harmful than cigarettes. Smokeless tobacco, cigar smoking, and waterpipe smoking have increased in usage over the past few decades. Some experts believe that their use is reaching epidemic proportions. Factors such as a perception of harm reduction, targeted advertising, and unrecognized addiction may drive the increased consumption of non-cigarette tobacco products. In particular, the need for social acceptance, enjoyment of communal smoking activities, and exotic nature of waterpipe smoking fuels, in part, its popularity. The public is looking for "safer" alternatives to smoking cigarettes, and some groups advertise products such as smokeless tobacco and electronic cigarettes as the alternatives they seek. Though it is clear that cigar and waterpipe tobacco smoking are probably as dangerous to health as cigarette smoking, there is an opinion among users that the health risks are less compared to cigarette smoking. This is particularly true in younger age groups. In the cases of smokeless tobacco and electronic cigarettes, the risks to health are less clear and there may be evidence of a harm reduction compared to cigarettes. In this article, we discuss commonly used forms of non-cigarette tobacco products, their impacts on lung health, and relevant controversies surrounding their use.

Direct-to-consumer genetic testing for addiction susceptibility: a premature commercialisation of doubtful validity and value

Genetic research on addiction liability and pharmacogenetic research on treatments for addiction have identified some genetic variants associated with disease risk and treatment. Genetic testing for addiction liability and treatment response has not been used widely in clinical practice because most of the genes identified only modestly predict addiction risk or treatment response. However, many of these genetic tests have been commercialized prematurely and are available direct to the consumer (DTC). The easy availability of DTC tests for addiction liability and lack of regulation over their use raises a number of ethical concerns. Of paramount concern is the limited predictive power and clinical utility of these tests. Many DTC testing companies do not provide the consumer with the necessary genetic counselling to assist them in interpreting and acting on their test results. They may also engage in misleading marketing to entice consumers to purchase their products. Consumers' genetic information may be vulnerable to misuse by third parties, as there are limited standards to protect the privacy of the genetic information. Non-consensual testing and inappropriate testing of minors may also occur. The United States Food and Drug Administration plans to regulate DTC genetic tests. Based on the ethical concerns we discuss below, we believe there is a strong case for regulation of DTC genetic tests for addiction liability and treatment response. We argue that until this occurs, these tests have more potential to cause harm than to contribute to improved prevention and treatment of addiction.

Would vaccination against nicotine be a cost-effective way to prevent smoking uptake in adolescents?

AIMS

We used epidemiological modelling to assess whether nicotine vaccines would be a cost-effective way of preventing smoking uptake in adolescents.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

We built an epidemiological model using Australian data on age-specific smoking prevalence; smoking cessation and relapse rates; life-time sex-specific disability-adjusted life years lived for cohorts of 100,000 smokers and non-smokers; government data on the costs of delivering a vaccination programme by general practitioners; and a range of plausible and optimistic estimates of vaccine cost, efficacy and immune response rates based on clinical trial results. We first estimated the smoking uptake rates for Australians aged 12-19 years. We then used these estimates to predict the expected smoking prevalence in a birth cohort aged 12 in 2003 by age 20 under (i) current policy and (ii) different vaccination scenarios that varied in cost, initial vaccination uptake, yearly re-vaccination rates, efficacy and a favourable vaccine immune response rate.

FINDINGS

Under the most optimistic assumptions, the cost to avert a smoker at age 20 was $44,431 [95% confidence interval (CI) $40,023-49,250]. This increased to $296,019 (95% CI $252,307-$355,930) under more plausible scenarios. The vaccine programme was not cost-effective under any scenario.

CONCLUSIONS

A preventive nicotine vaccination programme is unlikely to be cost-effective. The total cost of a universal vaccination programme would be high and its impact on population smoking prevalence negligible. For these reasons, such a programme is unlikely to be publicly funded in Australia or any other developed country.

On the futility of screening for genes that make you fat

J. Lennert Veerman discusses the implications for genetic screening of findings showing that physical activity substantially attenuates the effects of genetic variants which predispose towards obesity.

Integrating genetic studies of nicotine addiction into public health practice: stakeholder views on challenges, barriers and opportunities

OBJECTIVE

Will emerging genetic research strengthen tobacco control programs? In this empirical study, we interview stakeholders in tobacco control to illuminate debates about the role of genomics in public health.

METHODS

The authors performed open-ended interviews with 86 stakeholders from 5 areas of tobacco control: basic scientists, clinicians, tobacco prevention specialists, health payers, and pharmaceutical industry employees. Interviews were qualitatively analyzed using standard techniques.

RESULTS

The central tension is between the hope that an expanding genomic knowledge base will improve prevention and smoking cessation therapies and the fear that genetic research might siphon resources away from traditional and proven public health programs. While showing strong support for traditional public health approaches to tobacco control, stakeholders recognize weaknesses, specifically the difficulty of countering the powerful voice of the tobacco industry when mounting public campaigns and the problem of individuals who are resistant to treatment and continue smoking.

CONCLUSIONS

In order for genetic research to be effectively translated into efforts to minimize the harm of smoking-related disease, the views of key stakeholders must be voiced and disagreements reconciled. Effective translation requires honest evaluation of both the strengths and limitations of genetic approaches.

Pharmacogenetics of alcohol, nicotine and drug addiction treatments

The numerous premature deaths, medical complications and socio-economic repercussions of drug and alcohol addiction suggest that improvements in treatment strategies for addictive disorders are warranted. The use of pharmacogenetics to predict response to medication, side effects and appropriate dosages is relatively new in the field of drug addiction. However, increasing our understanding of the genetic factors influencing these processes may improve the treatment of addiction in the future. We examined the available scientific literature on pharmacogenetic advancements in the field of drug addiction with a focus on alcohol and tobacco to provide a summary of genes implicated in the effectiveness of pharmacotherapy for addiction. In addition, we reviewed pharmacogenetic research on cocaine and heroin dependence. Thus far, the most promising results were obtained for polymorphisms in the OPRM1 and CYP2A6 genes, which have been effective in predicting clinical response to naltrexone in alcoholism and nicotine replacement therapy in smoking, respectively. Opinions differ as to whether pharmacogenetic testing should be implemented in the clinic at this time because clinical utility and cost-effectiveness require further investigation. However, the data summarized in this review demonstrate that pharmacogenetic factors play a role in response to addiction pharmacotherapy and have the potential to aid in the personalization of addiction treatments. Such data may lead to improved cessation rates by allowing physicians to select medications for individuals based, at least in part, on genetic factors that predispose to treatment success or failure rather than on a trial and error basis.

Polygenic susceptibility to breast cancer: current state-of-the-art

Breast cancer is the most commonly occurring invasive cancer among women and its estimated incidence rate worldwide is approximately 1 million cases annually. Although several breast cancer susceptibility genes have been identified over the past two decades, it is likely that many genes with modest effects are yet to be found. In this review, we discuss the progress that has been recently made with the emergence of empirical genome-wide association studies for breast cancer and the identification of several common, low-penetrance disease alleles at loci that had not been previously implicated as candidates for breast cancer susceptibility. We also discuss the implications of these recent findings for risk prediction, targeted screening and public health interventions, and conclude by discussing the strengths and weaknesses of these studies, and the strategies required to identify additional risk factors for breast cancer.