A recent study sparked headlines about cancer risk from vapes, but what does it actually show us?
The research, published in the Cancer Research journal, found “similar” changes in cheek cells among people who vape and those who smoke.
Lead author Chiara Herzog, of the University of Innsbruck and University College London, told Filter that the aim was to investigate impacts of both smoking and vaping on the “DNA methylation footprint,” potentially indicating biomarkers for future cancer risk prediction.
The researchers, she said, were able to “identify epigenetic features associated with tobacco smoking in different cell types across the body, assess how these are altered in cancer or cells that turn into cancer in the future, and compare these changes in e-cigarette users with a limited smoking history.”
People in this last group “exhibited similar changes to the DNA methylation in oral epithelial cells as tobacco smokers,” Dr. Herzog said.
“Our study did not look at a direct link between e-cigarettes and cancer, and was not set up to demonstrate whether e-cigarettes cause cancer or not.”
One of her colleagues on the research team told media that vapes “might not be as harmless as originally thought,” while Herzog added, “we cannot assume they are completely safe to use.”
However, she made clear to Filter, “Our study did not look at a direct link between e-cigarettes and cancer, and the study design was not set up to demonstrate whether e-cigarettes cause cancer or not.”
This rather important disclaimer was comprehensively sidelined by a slew of alarmist media coverage.
“The interpretation of the media that the [study] authors showed that e-cigarettes cause cancer is wrong,” Derek Yach told Filter. Yach’s four decades in tobacco control have included past roles as a cabinet director and executive director for noncommunicable disease at the World Health Organization, and as the founding director of the Foundation for a Smoke-Free World.
Media misrepresentations, he said, are “dangerous for millions of smokers seeking to quit or switch from deadly cigarettes to relatively inert vapes.”
The narrative that vapes cause cancer has spread widely in recent years, as Yach noted. Harm reduction advocates have faced a daunting battle to bring public perceptions in line with the evidence.
One organization that seeks to do so is Cancer Research UK (CRUK). The charity posted a response to the new research, noting “some limitations to what the study was able to do.”
“Participants who vaped may have smoked in the past, so we can’t be completely sure that the changes seen weren’t caused by previous smoking.”
In particular, it said, “participants who vaped may have smoked in the past, so we can’t be completely sure that the changes seen weren’t caused by previous smoking.” There might be further variables at play, it added, and the cause of observed cell changes isn’t proven.
Herzog acknowledged that “further research is required” on the long-term health impacts of vaping.
The CRUK post concluded that people should not stop vaping if they run the risk of going back to cigarettes, which are responsible for at least 15 types of cancer.
“While this paper contributes to our growing understanding of e-cigarettes, and we will continue to fund more studies to build on this, more research is needed for us to make definitive conclusions,” Dr. Julie Sharp, head of health information at CRUK, told Filter. She reiterated that established evidence “suggests that e-cigarettes are far less harmful than smoking.”
CRUK has long stated, “There is no good evidence that vaping causes cancer,” and it retains that statement on its website.
Yach pointed out that the world has known for six decades that cigarettes are a potent cause of cancers due to toxic compounds released during combustion. But “in the original US Surgeon General Report of 1964, it was concluded that nicotine was not a cause of cancer—substantial research has confirmed this.”
“We need absolute clarity on what science shows: E-cigarettes and nicotine do not pose a threat to cancer,” Yach said.
Some other scientific experts have taken issue with the new research.
Peter Shields, emeritus professor of medical oncology at Ohio State University, said that “epidemiologically this study does not lead to the conclusions the authors claim, with a substantial weakness for their smoking/vaping analysis.” He described the data that the researchers relied on to determine subjects’ vaping or smoking status as “very crude.”
“The crucial question is not whether vaping has epigenetic changes … but how do vapers compare to smokers and never-smokers,” Shields continued. The researchers “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.”
“It’s important to highlight there were other changes in the cells of smokers that weren’t seen in e-cigarette users or non-smokers.”
“The paper finds that users of e-cigarettes had more hypermethylation in cells lining their cheeks, compared with never-smokers,” noted Associate Professor George Laking, director of the University of Auckland’s Centre for Cancer Research, and the researchers “say at least some of these changes were ‘similar’ to those seen in smokers.”
“One should beware of the word ‘similar,’ as it can have a lot of different meanings,” he continued. “For example, a lethal snake is in some ways ‘similar’ to a harmless earthworm. It’s important to highlight there were other changes in the cells of smokers that weren’t seen in e-cigarette users or non-smokers.”
It’s worth noting that tobacco harm reduction advocates have never claimed that vapes carry no potential harms whatsoever—only that they’re exponentially safer than the cigarettes they can replace. A 2015 landmark review in the United Kingdom estimated that vaping is “around 95 percent less harmful” than smoking, and UK health authorities have stuck to that position in the years since.
“Based on our study, we cannot say whether e-cigarettes cause cancer or not,” Dr, Herzog told Filter. “However, it is clear that cigarette smoking is linked to adverse health outcomes, and several studies have demonstrated that vaping can represent tools for smokers to quit more sustainably.”
Photograph by Vaping360 via Wikimedia Commons/Creative Commons 2.0
The Influence Foundation, which operates Filter, has received grants from the Foundation for a Smoke-Free World. Filter‘s Editorial Independence Policy applies.
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