Vaping linked to cancer that may damage body like smoking, new study claims

Vaping may lead to cancer in the same way as smoking tobacco, according to a new study.

E-cigarettes have soared in popularity as a way to help smokers kick the habit, but it turns out that it may not much different in terms of health.

Scientists have found that inhaling from a device that emits pure nicotine causes similar DNA changes to cells in the same way seen with cigarettes - and could result in a diagnosis. Findings highlight the importance of studying the long-term consequences of vaping, a relatively new practice.

Researchers at University College London and the University of Innsbruck in Austria saw DNA changes in cheek cells in vapers who rarely smoked that are often cited as the start of cancer in tobacco smokers. The latest research does not prove that vaping, which is still considered safer than classic smoking, causes cancer but raises questions over its potential harm.

Researchers analysed the epigenetic effects of tobacco and e-cigarettes on DNA methylation in more than 3,500 samples to investigate the impact on cells directly exposed to tobacco - such as those in the mouth - and those not directly exposed, such as those in blood or cervical cells.

The epigenome refers to an extra layer of information superimposed on our genetic material, or DNA. Whilst DNA is compared to the hardware of a computer, epigenetics are comparable to the computer’s software; defining how, where and when the programmes used by the computer are run.

Our epigenomes are constantly changing and can be affected by various genetic or nongenetic factors including ageing, our lifestyles, exposure to hormones, chemicals and environmental factors, and even stress and psychological trauma.

One commonly studied type of epigenetic modification is called DNA 'methylation'. The researchers discovered epithelial cells - cells that typically line organs and are often the cells of origin for cancer - in the mouth showed substantial epigenomic changes in smokers.

Crucially, these changes are further elevated in lung cancers or pre-cancer - abnormal cells or tissue that have the potential to develop into cancer - when compared with normal lung tissue. This gives weight to the idea that the epigenetic changes associated with smoking allow cells to grow more quickly.

However, the study, published in Cancer Research, also includes new data that shows similar epigenomic changes were observed in the cells of vapers who had smoked less than a hundred cigarettes in their lives.

Dr Chiara Herzog, of both the UCL EGA Institute for Women’s Health and the University of Innsbruck, said that though this didn't prove that vaping causes cancer, it demonstrated that it can't be assumed that this isn't the case.

"This is the first study to investigate the impact of smoking and vaping on different kinds of cells – rather than just blood – and we’ve also strived to consider the longer-term health implications of using e-cigarettes," Dr Herzog, the study's first author, explained.

"We cannot say that e-cigarettes cause cancer based on our study, but we do observe e-cigarette users exhibit some similar epigenetic changes in buccal cells as smokers, and these changes are associated with future lung cancer development in smokers."

She continued: "Further studies will be required to investigate whether these features could be used to individually predict cancer in smokers and e-cigarette users. While the scientific consensus is that e-cigarettes are safer than smoking tobacco, we cannot assume they are completely safe to use and it is important to explore their potential long-term risks and links to cancer.

"We hope this study may help form part of a wider discussion into e-cigarette usage - especially in people who have never previously smoked tobacco."

Through computer analysis of their samples, researchers also found some smoking-related epigenetic changes remain more stable than others after quitting smoking - including those in cervical samples, something that has never previously been looked at.

Professor Martin Widschwendter, also of UCL's EGA Institute for Women’s Health and the University of Innsbruck and a senior author of the study, added: “The epigenome allows us, on one side, to look back.

"It tells us about how our body responds to a previous environmental exposure like smoking. Likewise, exploring the epigenome may also enable us to predict future health and disease.

"Changes that are observed in lung cancer tissue can also be measured in cheek cells from smokers who have not (yet) developed a cancer. Importantly, our research points to the fact that e-cigarette users exhibit the same changes, and these devices might not be as harmless as originally thought. Long-term studies of e-cigarettes are needed."

It is well-known that tobacco is an undeniable contributor to adverse health outcomes. Smoking is estimated to have caused 7.69 million deaths across the globe in 2019 alone, with these numbers only predicted to rise in the coming years.

The NHS currently advises that e-cigarettes are substantially safer than smoking tobacco, and recommends smokers to switch to vaping to improve their health.

The UCL researchers now aim to further investigate how epigenetic changes related to smoking in cheek swabs could be used for identifying individuals at the highest risk of developing cancer and assess the long-term health risks of e-cigarettes.

Dr Ian Walker, Cancer Research UK’s executive director of policy, echoed the study's authors in highlighting the importance of future studies analysing the long-term health implications of vaping.

"This study contributes to our understanding of e-cigarettes, but it does not show that e-cigarettes cause cancer," he said. "Decades of research have proven the link between smoking and cancer, and studies have so far shown that e-cigarettes are far less harmful than smoking and can help people quit.

"This paper does however highlight that e-cigarettes are not risk-free, and so we need additional studies to uncover their potential longer-term impacts on human health. Smoking tobacco causes 150 cases of cancer every single day in the UK, which is why we look forward to seeing the Government’s age of sale legislation being presented in parliament.

"Nothing would have a bigger impact on reducing the number of preventable deaths in the UK than ending smoking, and this policy will take us one step closer to a smoke-free future."

The study was supported by funding from the European Union’s Horizon 2020 Research and Innovation programme, The Eve Appeal, and Cancer Research UK.

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