- Large scale review of 126 studies refutes ‘gateway theory’ that vaping leads to smoking
- Evidence suggests opposite could be true, that vaping leads to LESS youth smoking
- Among larger studies, smoking rates decreased as vaping rates increased
- Previous research from same team shows vapes help adults stop smoking
There is no clear evidence vaping leads young people onto more harmful smoking, a large scale review by leading health experts has found.
Public health researchers analysed 126 studies, with data from around four million people aged 29 and under across the U.S, Canada and Europe.
The major review, which used respected Cochrane methods, found no significant evidence to support the gateway theory – that young people who vape are more likely to go on to smoke.
As vaping rates increased, smoking rates decreased
Among the larger studies reviewed, data indicated that when vaping rates increased among youth, smoking rates tended to decrease. Conversely, when vaping access was restricted, smoking rates appeared to rise.
“One of the substantial concerns from some members of the public health community about vaping is that it might cause more young people to smoke,” says Jamie Hartmann-Boyce, assistant professor of health policy and management at the University of Massachusetts Amherst and senior author of the review.
“Some – but not all – evidence from our study possibly suggests the opposite – that vaping may contribute to declines in youth smoking, particularly in the U.S.”
The review, funded by Cancer Research, looked at the link between vaping and smoking on both an individual level and a population level. While individuals who vaped were found to be marginally more likely to go on to smoke, population-level data indicated vaping was unlikely to be the cause.
Hartmann-Boyce suggests that some youth who vape may have otherwise turned to smoking if vaping were not an option.
“There’s enough non-smoking kids who start vaping in the U.S. that if vaping was in a consistent and widespread way causing kids to start smoking, we would start seeing that in our population-level smoking data,” she says. “And we haven’t seen that at all.”
Cigarette smoking has steadily declined
In fact, cigarette smoking among youth has been steadily declining for years. Recent data from the U.S. Centres for Disease Control and Prevention (CDC) shows a sharp drop in high school students who reported smoking in the past 30 days – from 15.8 per cent in 2011 to 4.6 per cent in 2020 and just 1.7 per cent in 2024.
Tobacco Use among U.S. Middle and High School Students in 2024.
Source: CDC
“The smoking rates among kids have declined steeply, and whether or not that’s due to vaping or something else is up in the air,” Hartmann-Boyce says.
“But it’s difficult to argue that – in the U.S. population – youth vaping is en masse causing kids to smoke. The data doesn’t support that so far.”
The study, led by experts from some of the world’s top universities, emphasises that the findings are ‘low certainty.’ Unlike controlled experiments, where participants can be randomly assigned to behaviours, researchers cannot ethically assign adolescents to start vaping or smoking.
“The studies themselves are not straightforward study designs, because you can’t randomise kids to vape or not vape – it just wouldn’t be ethical,” Hartmann-Boyce explains.
He said more research is needed to more clearly ascertain cause and effect.
While most of the large studies reviewed suggest an association between increased vaping rates and declining cigarette smoking rates, other mostly smaller studies show conflicting results. “We need more studies to establish any causal links,” says Monserrat Conde, lead author from the University of Oxford.
The study concluded: “At a population level, the balance of evidence suggests that overall, youth vaping and smoking are inversely related – that is, as more young people vape, fewer smoke, and vice versa. However, this could vary by context and was not consistent across all studies.“
Previous research from Hartmann-Boyce’s team indicates that nicotine vapes can help adults quit smoking.
