- No significant link found between exclusive vape use and severe respiratory issues among people who have never smoked
- Associations with mild respiratory symptoms “tenuous and variable”
- Lack of studies looking only at vapers who have never smoked
- Researchers urge healthcare providers to encourage smokers to switch to less harmful vaping
Vaping is not scientifically linked with severe respiratory issues among people who have never smoked, a new evidence review has found.
The review of 12 studies in the U.S, led by professors from the University of Catania in Italy, found that eight reported no significant association between vaping and symptoms such as COPD, chronic bronchitis, emphysema, or asthma.
The remaining five studies reported at least one significant link – but the researchers concluded the methodologies used in four of these were “not robust.”
The report, published in the journal Internal and Emergency Medicine, said: “We included 12 studies with prospective designs that examine a range of respiratory outcomes subsequent to EC (electronic cigarette) use among PWNS (people who never smoked).
“Eight studies did not find statistically significant differences in respiratory risk associated with baseline EC use. The remaining five studies reported a significant association in at least one analysis, but in four of these studies, associations were not robust across models.”
Links to mild symptoms “tenuous”
The researchers said there was also little evidence of a link between vaping and moderate-to-severe respiratory symptoms, and even associations with mild symptoms was “tenuous.”
The review said: “Overall, evidence is lacking for moderate-to-severe respiratory risks associated with EC use, but there was a tenuous association with mild symptoms that was not robust across models and may be due, in part, to unaccounted-for confounding (other variables).”
The report said its findings show that moving away from conventional smoking – the leading cause of premature death globally – to vaping would have a positive impact on respiratory health.
It said: “While ECs are not completely risk-free, evidence to date suggests that shifting away from combustible tobacco toward ECs could have an overall positive impact on respiratory health of the population.”
The report says its findings should also calm any concerns that vaping itself causes moderate-to-severe respiratory issues in people who have stopped smoking entirely.
It said: “This evidence also alleviates concerns about moderate-to-severe absolute (independent of other factors) respiratory risks associated with long-term EC use by people who switched completely away from smoking.”
Lack of studies looking only at vapers who have never smoked
The researchers reviewed 12 studies from across the U.S. that looked specifically at the effects of vaping on respiratory health in people who have never smoked.
This removes the variable of past smoking, which most other studies have failed to adequately do.
Due to the small number of eligible studies for the review, the team accepted a broader definition of ‘never-smoking’. They included studies where participants had never had a single puff of a cigarette and those who had smoked less than 100 cigarettes in their lifetime.
The definition of respiratory outcomes also varied across the studies for the same reason. For example, three studies analysed self-reported asthma, two looked at wheezing symptoms, four analysed an index of self-reported respiratory symptoms, and one analysed any self-reported respiratory diagnoses (COPD, chronic bronchitis, emphysema, or asthma). Some looked at adults and others at young people.
‘Regulation should be risk proportionate’
The report says the studies are “reassuring in lacking statistically significant evidence of respiratory outcomes of EC use by both youth and adults who never smoked.”
However, due to the small number of studies available to review, they suggested additional research be carried out.
“Healthcare providers should encourage people who smoke and are unlikely to quit using other methods to switch completely to ECs and regulation should be risk-proportionate to incentivize people moving down the continuum of harm,” they said.
“However, this evidence is limited and imprecise and is over-reliant on U.S. samples. Additional research on possible health harms associated with EC use by PWNS, especially with larger samples, longer follow-ups, and more thorough control for confounding factors, is essential for understanding the population health impacts of ECs.”
