Vaping, Like Smoking, May Cause ‘Similar Damaging Changes’ to DNA

The cells of people who vape have been found to contain changes to DNA similar to those seen in the cells of smokers.

These changes in cell DNA, known as epigenetic changes, were found in cells directly exposed to the smoke and vapor—like the mouth—and in those indirectly exposed, such as in the blood or the cervix, according to a new study in the journal Cancer Research.

While this doesn’t mean that vaping has the same degree of cancer risk as smoking does, it implies that vaping may have negative health impacts that we have yet to discover.

“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,” said study author Chiara Herzog, a researcher at University College London’s EGA Institute for Women’s Health and Austria’s University of Innsbruck, in a statement.

“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 [cheek] cells as smokers, and these changes are associated with future lung cancer development in smokers,” she said. “Further studies will be required to investigate whether these features could be used to individually predict cancer in smokers and e-cigarette users.”

The study describes how over 3,500 samples of body cells were tested for the epigenetic effects of tobacco and e-cigarettes on DNA methylation.

Epigenetic changes are alterations in gene expression that do not involve changes to the underlying DNA sequence. These changes can influence how genes are turned on or off, which can affect the way cells function. Epigenetic modifications include DNA methylation, which is the process of adding a methyl group to DNA molecules and often results in gene silencing—preventing the transcription machinery from accessing the gene and therefore inhibiting gene expression.

Epigenetic changes can be triggered by a number of factors, including aging, hormone or chemical exposure, stress and environmental factors.

The study’s authors describe how they found epigenomic changes in the cells of e-cigarette smokers, which are also seen in lung cells that are cancerous or precancerous.

Andrew Beggs, a professor of cancer genetics and surgery at the U.K.’s University of Birmingham who wasn’t involved in the study, said in a statement: “This interesting study shows e-cigarette use is associated with similar damaging changes in methylation in human cells as smoking. Although it doesn’t show a direct causal effect, this study shows that further research must be done to understand the effects of e-cigarettes on human health and whether they could be linked to an increased risk of cancer.”

These changes were also seen in the cheek cells of vapers, who had smoked fewer than 100 cigarettes in their lives.

“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,” Herzog said. “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.”

Smoking tobacco has long been established as a cause of cancer, killing over 8 million people each year, of which 1.3 million are nonsmokers who are exposed to secondhand smoke.

Martin Widschwendter, a professor of cancer research at University College London, told Newsweek: “While it was known that smoking can modulate the epigenome, it was not known how it influences different cell types and whether responses would be similar or impacting different genes and biological pathways. Our findings indicate that smoking changes the epigenome in different cell types across the body in a different manner.”

Other experts have concerns about the findings in the new study.

“The journal Cancer Research is a really high-quality journal, but epidemiologically this study does not lead to the conclusions the authors claim, with a substantial weakness for their smoking/vaping analysis,” Peter Shields, an emeritus professor of medical oncology at Ohio State University who wasn’t involved in the study, said in a statement

He said there are limitations to the study that the authors don’t discuss, such as the fact that the researchers combined disparate types of study sets without looking into any confounding factors.

“To make their claims of adverse effects, there are critical pieces of information that are missing,” Shields said. “They do not have good vaping/smoking data so mostly rely on each person saying yes/no, or self-reporting years of use. This is very crude and without the dose-response assessment (e.g., packs per day, vapes per day, etc.), they are still a far distance from being able to show causality. For the vapers, there was no biochemical verification that they were actually not also smokers.”

He continued: “The crucial question is not whether vaping has epigenetic changes (which we cannot say establish a risky cell type or a physiological protective mechanism to prevent disease) but how do vapers compare to smokers and never-smokers.

“They really do not explore that well, but in fact the data looks like vapers are actually more like never-smokers — implying their risk of cancer is not increased by vaping! This is not discussed. The authors really need to be more cautious,” Shields said.

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