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E-cigarettes are in the news again. This time with headlines that they may cause cancer.
But the study that the stories are based on, published in the journal PNAS, doesn’t show this.
What did the study do?
Researchers from New York University School of Medicine looked at how e-cigarette vapour affected the DNA of mice, and human cells in a dish.
They didn’t look at how it affected people. And they didn’t directly compare it to smoking.
The researchers focused on how components of e-cig vapour damage cells’ DNA. And DNA damage increases the risk of cancer.
But they didn’t look directly at whether e-cigs caused cancer, either in mice or in people.
What did the study show?
They found that e-cig vapour raised levels of DNA damage in the lungs, bladders and hearts of mice.
They also found that the molecular machinery cells use to repair this DNA damage was less effective in the lungs of mice exposed to e-cig vapour.
Then they looked at how nicotine, the chemical that e-cigs vaporise, affects human lung and bladder cells grown in a lab dish. Nicotine is what makes cigarettes addictive, but isn’t what causes the damage from smoking. Both e-cigarettes and conventional cigarettes contain nicotine, but e-cigs have much lower levels of the harmful components of tobacco smoke.
The researchers found that nicotine damages the DNA inside those lab-grown human lung and bladder cells. And they found that these cells were less able to repair this damage. These cells were then more susceptible to further genetic faults that could give them properties like those of cancer cells.
What do the results mean?
The researchers described their results with an interesting line:
“It is therefore possible that e-cigarette smoke may contribute to lung and bladder cancer, as well as heart disease, in humans.”
While this is technically possible, the study didn’t look at humans, and so didn’t show any effect on the health of humans.
Different e-cigs devices deliver different amounts of vapour, and people use them in different ways. So the levels of e-cig vapour and nicotine used in the study might not match the levels that people are exposed to through normal use.
And other research didn’t show a link between nicotine products and cancer.
Finally and crucially, the study didn’t compare vaping to tobacco smoke.
The evidence so far shows that e-cigarettes are far less harmful than smoking.
And for some people they’re a helpful aide to stop smoking.
Up to two-thirds of long term smokers will die because of their addiction. E-cigarettes don’t contain tobacco, which is the biggest cause of preventable death worldwide.
E-cigs are a relatively new technology and so we can’t be certain about any long-term effects the devices might cause to health – they haven’t been around long enough for this to be completely worked out. But compared to smoking, the evidence so far shows they are less harmful.
Studies like this are important for building up the evidence around vaping, and how e-cig vapour might damage cells in controlled conditions. It’s a small piece in the puzzle, and must be viewed alongside other studies. Large, long-term studies are also needed to definitively answer health questions, because those conclusions can’t be made from lab-grown cells and mice alone.
The popularity of e-cigs continues to grow, but figures show that most people using these devices are now ex-smokers, and people mainly use them to quit smoking or cut down.
So conclusions around the health effects of vaping must be viewed alongside the damage that smoking has wreaked for decades. Only then can smokers make a call that could have a big impact on their health.
If you want to quit smoking you can find support to help you here, and find out about your local Stop Smoking Services here.
Spooky January 31, 2018
I’m a vaper, but I really tried to keep an open mind while reading the findings of this study. However, after reading a statement by lead-author Moon-shong Tang, I decided that it’s nothing more than junk science. Asked if smoking was still more harmful than vaping, he said “We don’t know which one is more harmful”. Really? You find some DNA damage in mice and petri dish cells after exposing them to vaporized high-nicotine e-liquid and all of a sudden they’re potentially more dangerous than those carcinogen-infested death sticks? Now I know why they didn’t compare e-cig vapor to cigarette smoke in the study.
Simon Williams January 31, 2018
I’m another who’s been able to give up a significant cigarette habit only because of vapes. Really has worked for me the past few years. Reassuring to read informed and educated analysis about the relative risks involved. Wish this level of insight was present in some of the media coverage to start with so rebuttal wasn’t needed so frequently. I hope policy decisions will be continue to be evidence led, rather than see vapes placed under increasingly onerous regulations which aren’t supported by the research.
Jason B. January 31, 2018
First off all your doing is spreading lies. These posts are completely unfounded with any clinical proof . When every study done by actual Doctors prove the complete opposite of this trash.
Kenneth Kawa January 30, 2018
Based on what I suspected which was bad research practices it prompted me to research this specific study a bit more in depth. So what did I find?
Quote from the Study: “E-cigarette aerosols from NJOY top fill tanks (NJOY, Inc.) filled with 1.6 mL of e-juice with 10 mg/mL nicotine in a propylene glycol/vegetable glycerin mixture (50/50 by volume; MtBakerVapor MESA). Each day the tanks were filled with fresh e-juice from a stock mixture, and the voltage was adjusted to produce a consistent wattage (∼1.96 A at 4.2 V) for each tank.”
They tested the atomizers at 4.2 volts.
I decided to go to the Njoy website to research further and found This: https://i.imgur.com/6YyaKVD.jpg
All NJOY Vape Pen Batteries (including the NJOY Pre-Filled Tank Battery) operate at 3.7V when fully charged.
The NJOY Vape Tank has an atomizer resistance of approximately 2.1 ohms. We do not recommend using NJOY Vape Tanks or NJOY Pre-Filled Tanks with other batteries since we have not tested those.
NJOY specifically states not to use the tanks at over 3.7v, they are specifically designed to be used at 3.7v, the tests were done at 4.2 volts, all the data and time put into this study is a complete waste.
Daniel O'Callaghan January 30, 2018
I quit smoking through vaping 3 years ago, I now run a UK based e-liquid manufacturer and have helped thousands on their journey away from tobacco, it amazes me how such powerful Newspapers can make such crazy claims, which are just untrue, what is their agenda? to sell more papers? They never attack smoking, in fact, they actively promote the tobacco companies slightly less harmful alternatives, the last time they did was last month, claiming a study done by the tobacco company themselves had said so. Thank you Cancer research for writing this, I think by pointing this out more lives can be saved, and less sensationalist newspapers will be sold!
Louise carter January 30, 2018
I quit smoking 4 years ago but have used an e-cig since then. I never thought I’d give up using the e-cig but got a terrible cough at Christmas and haven’t used it for 4 weeks now. I always used plain tobacco flavour and went from a high dose right down to low. I’m not craving it anymore but occasionally think about it when having a drink as I always used it then. It definitely got to be more of a habbit than a need for nicotine in the end. Anyway ….. 4 weeks so far. Wish me luck x