Quitting cigarettes but vaping still raises lung cancer risk

Quitting cigarettes – A large study of more than 4.5 million adults found that people who quit cigarettes but still used e-cigarettes had a substantially higher risk of lung cancer death than those who stopped completely. Researchers stress that vaping to help quit smoking appears

On a quiet but consequential line of risk, the question isn’t whether quitting smoking helps. It does. The new question is what happens to that protection when someone swaps cigarettes for vapes.

A study tracking more than 4.5 million adult smokers in South Korea found that smokers who quit cigarettes but continued vaping had a more than 50 per cent higher chance of developing lung cancer than people who stop entirely. The work also reinforces a different message that is just as important for anyone trying to quit: using e-cigarettes to help quit is safer than continuing to smoke.

Becky Freeman at the University of Sydney, Australia—who wasn’t involved—put it bluntly. “The study adds to the rapidly growing body of evidence that e-cigarettes are absolutely not as low-risk as initially claimed. ” she said. She urged people trying to quit smoking to “try other safer [but] effective methods first. ” using e-cigarettes only after exhausting other options if quitting isn’t possible.

The study comes as vaping has already become part of how some smokers try to quit. Just over 40 per cent of smokers in the UK who quit the habit in 2024 used e-cigarettes to help the process, and 20 per cent of ex-smokers were vaping a year or more after ditching cigarettes.

Those numbers sit in a wider context where e-cigarettes have been linked to airway irritation and reduced lung function. They’ve also been tied to lung cancer in animal studies, alongside concerns seen in human research—supporting why this new dataset matters.

To understand what vaping does in the real world. Yeon Wook Kim at Seoul National University in South Korea and his colleagues followed more than 4.5 million adult smokers in the Korean National Health Screening Programme from 2018 to 2023. Participants were grouped as current smokers. short-term quitters—those who hadn’t smoked since at least 2018—and long-term quitters—those who hadn’t smoked since at least 2014.

Across that period, from 2018 to 2023, the researchers recorded 35,887 cases of lung cancer and 12,807 related deaths among the participants.

When the team looked at the data through the lens of self-reported e-cigarette use, the pattern sharpened. Risk of lung cancer death was substantially higher among vaping ex-smokers than among those who did not vape. “Compared with those who completely quit cigarettes. individuals who used e-cigarettes after quitting had a 56 per cent higher risk. ” Kim said.

Kim and his team caution that the study can’t prove vaping itself causes lung cancer. Longer-term studies are still required, and further work is needed that includes people outside South Korea.

Even so, the paper points to biological reasons researchers are watching closely. Some chemicals in e-cigarettes have been linked to DNA damage. Vaping has also been associated with oxidative stress—an imbalance between molecules called free radicals and antioxidants in the body that can drive cell damage—along with epigenetic changes. where our genes are influenced by our environment. and inflammation in respiratory and oral tissue.

There’s a competing thread in the results, one that complicates any simple “vaping is bad” takeaway. The study found the risk of death from any cause was significantly lower among ex-smokers who used e-cigarettes than among current smokers. In other words. switching away from cigarettes still appears to deliver major health benefits. even if vaping doesn’t erase every risk.

Nicole Lee at Curtin University in Perth, Australia, said the message is grounded in that trade-off. “The message of the study seems to be that completely stopping both smoking and vaping offers greater protection against lung cancer than quitting smoking but continuing to vape,” she said.

She added that the findings don’t change the safest bottom line—quitting completely is still the goal. “It doesn’t change the advice to smokers that quitting completely is safest,” Lee said. “But if you can’t quit [without the use of e-cigarettes] or don’t want to. switching to vaping is still safer.” She emphasized the harm-reduction framing: “Vaping isn’t harmless. but [as] a harm-reduction approach. it’s much better than continuing to smoke.”.

Bernard Stewart at the University of New South Wales in Sydney said further studies are required before any public health initiatives—such as additional restrictions on vapes—are rolled out.

For people trying to quit, the headline isn’t that e-cigarettes make quitting meaningless. It’s that they may not fully close the door on lung cancer risk once cigarettes are gone. The sharpest protection. according to the study. comes from stopping both—vaping included—though the research also makes clear why many public health discussions will still wrestle with the reality of addiction. access to alternatives. and what people can realistically do when “quit cold turkey” isn’t on the table.

vaping e-cigarettes lung cancer risk smoking cessation harm reduction DNA damage oxidative stress epigenetic changes inflammation South Korea Korean National Health Screening Programme