In October, we posed 9 new challenges to the research community, each with the potential to change the way we think about cancer. Through our blog series, members of our Cancer Grand Challenges Scientific Committee reflect on where a global, multidisciplinary team could take us with each challenge. Here, Professor David Hunter shares his thoughts on e-cigarettes.
The most common cause of cancer death is lung cancer. And the most common preventable cause of lung cancer is smoking. So, what would happen if we eliminated smoking tomorrow? After the latency period from exposure to disease has passed, we could eliminate an estimated 22% of global cancer deaths.
We’ve made strong progress in reducing the global toll of tobacco use, thanks to many effective interventions, such as financial disincentives, advertising restrictions and smoke-free laws, as well as the galvanizing effect of the WHO Framework Convention on Tobacco Control. But progress is often slowed by the tobacco industry’s efforts to undermine these interventions. And while tobacco use has decreased in high-income countries, similar gains have not been seen in many low- and middle-income countries. If we are to reduce deaths from cancer over the coming decades, we need to redouble our efforts to prevent and reduce tobacco use.
It’s in this context that we find ourselves trying to understand the full effects of e-cigarettes on society and public health. Since their entry to the marketplace, we’ve seen substantial debate – for example, the extent to which they may be helpful for smokers trying to quit, or whether they could roll back hard-fought gains in reducing tobacco use – alongside rapidly emerging data about their short-term, and potential long-term, health effects.
The considerations for adult smokers are complex. In many cases, smokers turn to e-cigarettes in an effort to reduce their cigarette consumption or to quit completely. But quitting is difficult, and it’s often not an either/or situation. These devices are frequently used alongside cigarettes (dual use) or become more like a long-term substitute – although use patterns may vary substantially between different countries. And although e-cigarette aerosol generally contains fewer tobacco-related toxicants than cigarette smoke, it can contain carcinogens and other toxicants. What we’re really talking about here is the possibility of risk reduction for smokers who find e-cigarettes help them quit smoking for good.
We need to be careful that potential benefits for adult smokers do not come at the expense of youth. While consumer preferences, such as flavourings, may contribute to e-cigarettes’ potential for smoking cessation, they also appeal to kids, encouraging them to vape and exposing them to health risks – this is especially evident in the US, where the prevalence of e-cigarette use in youth far exceeds that of adults. It’s also important to consider the adverse effects of nicotine exposure during adolescence, which includes addiction and potential harm to the developing brain in terms of learning, memory and attention, and priming the brain for addiction to other drugs.
We need to answer biological questions about the pathophysiological impact of e-cigarette use, to understand more about their short and long-term health consequences and their patterns of use by various populations. We need risk analysis that takes this information and seeks to understand it in the context of the theoretical risk reduction for adult smokers who use e-cigarettes to completely quit smoking and the potential harm imposed by increased uptake amongst young people and non-smokers.
These types of analyses are complicated by several factors, including the rapid evolution in products, an industry actively promoting their use, and the need to take into account the country context. There are vast differences between countries in both regulatory capacity and tobacco control infrastructure, which makes it difficult to make broad generalisations or suggest a one-size-fits-all approach to regulating e-cigarettes. We need research into effective, appropriate ways of regulating the industry to create healthier societies.
The global outlook at the core of Cancer Grand Challenges will be very important for the e-cigarette challenge, as about 80% of cigarette smokers live in low- and middle-income countries. We need teams to approach this challenge open-mindedly, and not just try to prove their own viewpoint. An international team of population scientists, toxicologists, biologists, analytical chemists, behavioural psychologists and other relevant disciplines – with members who reflect the different public health contexts of their countries – will automatically build some of that diversity of thought in, and foster the kind of collaboration and creativity this challenge needs.
Over the past 10 years, the e-cigarette landscape – the products, their use, the regulatory strategies implemented by countries around the world – has undergone dramatic change. Over the next 5 years, as research teams take up this challenge, this will likely continue to do so. This challenge represents an important opportunity to develop strong evidence to support individual and population health, and to inform the global effort to reduce disease and death from tobacco use.