vaping after – A study following more than 4.5 million adults in South Korea finds that people who quit cigarettes but continued vaping had a substantially higher risk of dying from lung cancer than those who stopped completely. Researchers say the results cannot prove vapin
For people who managed to kick cigarettes, the relief can be sharp—and short-lived. The new evidence coming out of South Korea is aimed at a specific group: ex-smokers who quit smoking but kept vaping.
In a study of more than 4.5 million adults. those who used e-cigarettes after quitting had a 56 per cent higher risk of lung cancer death than people who completely stopped both smoking and vaping. The research also found that ex-smokers who vaped had a lower risk of dying from any cause than people who were still smoking—reinforcing a message that quitting remains the clear goal.
Becky Freeman at the University of Sydney. Australia. who was not involved in the work. said the study adds to “the rapidly growing body of evidence that e-cigarettes are absolutely not as low-risk as initially claimed.” She stressed what she believes should come first: “It’s important that people who are trying to quit smoking try other safer [but] effective methods first. and only use e-cigarettes after exhausting other methods if they are unable to quit.”.
The figures offer a glimpse into how common this “quit but vape” path has become. Just over 40 per cent of smokers in the UK who quit the habit in 2024 used e-cigarettes to help them do it. And a year or more after stopping, 20 per cent of ex-smokers were still vaping.
Those numbers matter because vaping has not been framed as a long-term substitute with no consequences. Prior research has linked e-cigarettes to airway irritation and reduced lung function. and animal studies have suggested associations with lung cancer. The new study tries to answer a different question—what happens in real people, over time, after cigarettes are gone.
Yeon Wook Kim at Seoul National University in South Korea and his colleagues tracked more than 4.5 million adult smokers who took part in the Korean National Health Screening Programme between 2018 and 2023. The participants were sorted into three groups: current smokers. short-term quitters (people who hadn’t smoked since at least 2018). and long-term quitters (people who hadn’t smoked since at least 2014).
Across the study period, there were 35,887 cases of lung cancer and 12,807 related deaths among the participants from 2018 to 2023.
When the researchers looked at lung cancer death risk alongside self-reported e-cigarette use. the pattern turned uncomfortable for anyone hoping vaping is a harmless “bridge” once smoking is over. Kim said that. compared with those who completely quit cigarettes. “individuals who used e-cigarettes after quitting had a 56 per cent higher risk.”.
The study doesn’t end there, and it doesn’t try to overreach. Kim and his team emphasized they couldn’t prove that vaping itself causes lung cancer, and they said further studies are required, including research that includes people outside South Korea.
Still, the authors point to biological signals that could help explain why vaping may not be risk-free. Longer-term studies are needed, but some chemicals in e-cigarettes have been linked to DNA damage. Vaping has also been associated with oxidative stress—described as an imbalance between molecules called free radicals and antioxidants in the body that can cause cell damage—as well as epigenetic changes. where genes are influenced by the environment. and inflammation in respiratory and oral tissue.
A second finding lands like a counterweight: the risk of death from any cause was significantly lower among ex-smokers who used e-cigarettes than among current smokers. That result is part of what shapes the message health experts are careful to repeat: stopping cigarettes is the priority. even if vaping carries additional risks.
Nicole Lee at Curtin University in Perth. Australia. said the study’s message seems to be that completely stopping both smoking and vaping offers greater protection against lung cancer than quitting smoking but continuing to vape. “The findings are very relevant for people who have quit smoking,” she said.
Lee said the study does not change the advice that quitting completely is safest. but she added that for people who can’t quit without e-cigarettes—or don’t want to—switching to vaping is still safer. “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 agreed that more evidence is needed before any sweeping policy moves. He said further studies are required before public health initiatives, such as further restrictions on vapes, are rolled out.
For many ex-smokers, the study doesn’t offer a neat ending. It suggests a spectrum of risk rather than a simple yes-or-no. The most protection comes from being done with cigarettes—and being done with vaping, too.
vaping e-cigarettes lung cancer smoking cessation harm reduction DNA damage oxidative stress epigenetic changes inflammation Korean National Health Screening Programme