New research on Monday is another indication that vaping is not a completely safe alternative to smoking. thought to be. Researchers say they found evidence in mice that a pair of e-cigarettes can cause certain cancers. But we still have a long way to go to find out if this is true in humans and how high the risk of cancer can cause it.
There are hints that e-cigarette vapors, like tobacco smoke, can be carcinogenic. In a previous study by the same group of researchers at New York University School of Medicine, they found that vaping could damage DNA in bladder and lung cells of both mice and humans to increase their risk of developing cancer. Other scientists have discovered the presence of chemicals that are known to be carcinogenic in a pair of electronic cigarettes, especially from flavored products. But a new study published by PNAS may be the first to directly link e-cigarettes to cancer.
"The probability is very high that e-cigarette pairs are a human carcinogen."
In a study, researchers experimented with mice for just over a year. For 54 weeks, they subjected the mouse groups to three different conditions, each lasting four hours a day, five days a week. One group of mice spent time in a chamber filled with pairs of electronic cigarettes created by a machine that mimicked a typical vaping product, that is, nicotine was heated and aerosolized from a liquid containing propylene glycol solvents and vegetable glycerol. Another group was subjected to evaporated air, which simply contained solvents, and a third simply spent their time breathing filtered air.
At the time of completion of the experiment, nine of the 40 mice (22.5 percent) exposed to typical e-cigarette pairs were lung cancer, whereas only one mouse in any control group did the same. More than half of the e-cigarette vapor group also developed advanced bladder (a condition called hyperplasia), a risk factor for bladder cancer, compared to one mouse who did the same in both control groups.
According to lead author Moon-Shong Tang, a molecular biologist at NYU, the team also found that certain cancer-causing compounds, called nitrosamines, are formed in the bodies of mice by exposure to nicotine-filled vapors. These nitrosamines are known carcinogens to both mice and humans.
"So it is very likely that a pair of e-cigarettes is a human carcinogen," Tang Gizmodo said in an email.
The team's conclusions are scary, as they are, with some important limitations. Mice, of course, are not humans, but the type of mouse used by Tan and his team is more sensitive to cancer-causing chemicals during their one-year life span than other mice. These mice are often used in cancer research because it usually takes a long time to determine if a particular thing can cause cancer (meaning that they are not genetically susceptible to lung cancer). Thus, although this study may indicate that e-cigarette pairs may be cancerous, it cannot predict how carcinogenic it can be in humans.
There is a similar gap when it comes to figuring out how many e-cigarettes with cancer risk are compared to traditional tobacco smoking. At this point, Tan assured, there is no point in how relatively carcinogenic vaping can be when stacked against smoking. And the authors wrote that their results should not lead the public to "equalize the risk" of smoking smoking.
At the same time, some health experts and organizations claim that e-cigarettes are about 95 percent less harmful than tobacco cigarettes. Much of this calculation was based on evidence that nicotine itself is not carcinogenic or that vaping barely exposes people to its cancer by-products, nitrosamines. But if Tan and his team really find something here, the 95 percent figure may lie on shaky ground.
In any case, the debate is unlikely to be resolved in the near future, even if studies on both mice and humans continue.
"It takes two decades or more for a smoker to live to develop lung cancer," Tang noted. "If tobacco smoke-induced lung carcinogenesis is a paradigm for e-cigarette carcinogenicity, it will take at least a decade for human lung cancer associated with an e-cigarette."
In other words, it will be a long time to study losing people to truly know what the risk is – and that leaves a more immediate, potentially deadly risk of using unregulated vamping products.