Does vaping harm the lungs of adults who have never smoked?
Posted on April 24, 2024 By Colin
RESEARCH HAS NOT IDENTIFIED any serious harms to the lungs from vaping nicotine by non-smoking adults in the short-medium term. An expert review concluded that vaping nicotine is unlikely to raise any significant concerns for lung health. (Polosa)
There is good evidence that lung health improves in smokers who switch to vaping. Breathing, cough and reduced phlegm improve (Hajek) and there are short- to medium-term improvements in asthma (Polosa), chronic obstructive pulmonary disease (emphysema) (Polosa), muco-ciliary (phlegm) clearance (Polosa), respiratory infections (Miler; Lucchiari) and lung function (Cibella). These changes are likely to persist over the longer term. Furthermore, the lung cancer risk from vaping is estimated to be 50,000 times less than from smoking. (Scungio)
What does the evidence say about non-smokers?
In Australia, vaping by never-smoking adults is rare. In a study in 2020, only 1% of current Australian adult vapers had never smoked (3/307). (Larcombe) This is similar to Great Britain where only 1.1% of never-smokers currently vape. (ASH UK)
The way to identify harm from vaping in never-smokers is with “longitudinal” studies which monitor changes over time. These longitudinal studies have not found significant harmful effects so far on lung health.
- Non-smokers may get transient throat irritation, cough or wheeze. However, there is no evidence to suggest that this may lead to clinically significant harm. (Polosa)
- A 2-year longitudinal study in 2024 by Karey found “no significant association … between e-cigarette use [in never-smokers] and important respiratory symptoms”. In a similar study, Reddy also found no increase in respiratory symptoms after 12 months in never-smokers who vaped.
- A 2-year study by Sargent found that “no significant association was detected between e-cigarette use and important respiratory symptoms”, concluding that respiratory symptoms were “largely not significantly different from never or former tobacco users”.
- Polosa studied nine daily vapers who had never smoked and found no evidence of lung damage after 3.5 years. There were no respiratory symptoms, no changes in lung function, markers of inflammation or change in lung scans.
- Kenkel found no evidence of respiratory disease in a longitudinal study over 3-years of 12 never-smokers who vaped.
- Sanchez-Romero found that exclusive vaping in never-smokers did not increase the risk of wheezing in a national study over 5 years in the US. However an increase in wheezing was reported in smokers.
- Berlowitz reported a reduction in cough but found an increase in wheezing in non-smoking vapers. The significance of the results has been questioned because of the low numbers, reliability of self-reports, possible other explanations and uncertain clinical significance.
Contrary to media reports, vaping nicotine does not cause the serious lung disease EVALI (Mendelsohn), “popcorn lung” (CRUK) or spontaneous pneumothorax.
This review does not include studies in smokers who switch to vaping as the results are confused by prior damage caused by smoking. It does not include cross-sectional studies which cannot determine causation.
A review of studies in young people who vape also found no clinically significant lung symptoms or triggering of asthma. (here)
What about laboratory studies?
Cell studies have found that vaping can cause oxidative stress, inflammatory changes and DNA damage, although these changes are much less than from smoking. (Wang; Caruso; Emma) Findings from cell and animal studies are often not a reliable guide to human effects and should be treated with caution. (Bracken)
Conclusion
Vaping is not risk-free and it is not recommended for non-smokers. However, vaping is clearly far less harmful to the lungs than smoking because of the substantial reduction in exposure to toxins. The research so far has not found significant concerns to the lungs from short-medium term use.
Nevertheless, it is possible that respiratory harm from vaping may become apparent from many years of use, especially in long-term and heavy users, and continued investigation is needed.
Acknowledgement
Thank you to Professor Riccardo Polosa for reviewing this analysis.