Highlights
- Experts say new University of York review linking teen vaping to smoking relies mainly on low-quality evidence and cannot prove causation.
- Recent studies, including those from QMUL and UMass, suggest little evidence of a “gateway effect” and even possible contributions to falling youth smoking.
- Retailer VPZ backs strict underage sales enforcement while highlighting vaping’s role in adult harm reduction.
A new umbrella review linking youth vaping with later smoking and a range of health problems has sparked headlines – but experts are warning against drawing firm conclusions from the findings.
The study, led by the University of York and the London School of Hygiene and Tropical Medicine and published in Tobacco Control, concluded that e-cigarette use among teenagers is consistently associated with increased likelihood of smoking, as well as possible links to asthma, mental health issues and substance use.
Yet leading academics stress the evidence base is weak. Prof Kevin McConway, Emeritus Professor of Applied Statistics at The Open University, pointed out that 53 of the 56 systematic reviews assessed were of “low” or “critically low” quality. “It’s pretty well impossible to conclude that the associations…are causal,” he said, adding that the findings may reflect risk-taking tendencies rather than the effects of vaping itself.
Dr Emma Beard of University College London said the press release “presents an overly strong conclusion that is not fully supported by the data” and warned against overspeculation about a so-called ‘gateway effect’, particularly as smoking rates have declined while vaping has risen.
“While protecting youth is vital, this review clearly shows the current evidence base on this topic has some significant weaknesses,” Dr Beard said.
Prof Ann McNeill, Professor of Tobacco Addiction at King College London, also questioned the ‘gateway effect’, noting that their research showed the opposite relationship – that trying a tobacco cigarette was associated with subsequent vaping.
Dr Richard Holliday, Senior Lecturer at Newcastle University, added that the omission of the confounding effects from tobacco smoking from the analysis “undermines their conclusion that there are ‘significant associations’ between vaping and oral health harms.”
Other researchers have made similar points in response to recent studies on the same theme. A July 2025 intergenerational analysis suggested UK teens who vape are as likely to smoke as their 1970s peers – but UCL’s Prof Lion Shahab said the interpretation was “problematic” because the direction of the relationship could not be established. Queen Mary University of London’s (QMUL) Prof Peter Hajek added that the findings more likely reflect shared risk preferences, “in the same way that compared to teetotallers, drinkers of white wine are more likely to also try red wine.”
Earlier this year, US researchers writing in Addiction reported “very low-certainty evidence” that vaping causes smoking – and suggested that in some cases the opposite may be true, with vaping contributing to declines in youth smoking. Similarly, a major NIHR-funded study led by QMUL in 2023 found no evidence at a population level that e-cigarettes promote smoking, and even tentative signs that they may be accelerating its decline.
Despite the contested evidence, the York researchers argue their findings justify precautionary policies to restrict youth access.
“Our previous reviews have shown that commonly used marketing strategies for e-cigarettes on social media networks resulted in more young people vaping, and this new review looks at what happens when vaping is a regular practice,” Su Golder, Associate Professor in Health Science at the University of York, said.
“These findings support stronger public health measures to protect teens from the risks associated with vaping.”
Mark Oates, founder of campaign group We Vape, said fear-mongering about "this vital, life-saving harm reduction tool is irresponsible and undermines efforts to end smoking,” as he called on the government to launch mass awareness campaigns to counter misinformation.
“Currently, 57 per cent of smokers in England wrongly believe vaping is as harmful or worse than smoking, when vaping is a far safer way to consume nicotine. This has to change if we are serious about making the UK smoke free and saving lives,” Oates added.
Vape retailer VPZ said it backed tougher enforcement.
"While the review highlights concern about young people experimenting with e-cigarettes, it is equally important to separate this from the wider role vaping plays in harm reduction,” Operations Director Jamie Strachan commented.
“In the UK alone, vaping has been shown by independent bodies such as Public Health England and the NHS to be significantly less harmful than smoking and the most effective tool available to help adults quit cigarettes.
“We echo the call for robust enforcement to ensure that all retailers uphold the law. There must be a clear distinction between legitimate, regulated businesses who support smoking cessation, and those who act irresponsibly by targeting underage customers.”