November 11, 2026

expert reaction to a study looking at the effects of e-cigarette use on pulmonary function

Scientists react to a study published in Tobacco Control* looking at the effects of e-cigarette use on pulmonary function.

Dr Katie East, Associate Professor in Public Health, Brighton and Sussex Medical School (BSMS), said:

“This is a small-scale pilot study of 22 people who had vaped in the past 30 days, with no control group. Possible confounding with use of other tobacco products cannot be ruled out, since participants were eligible if they smoked five or less combustible tobacco products in the past month. While forced expiratory volume declined as vaping frequency increased, this trend was not statistically significant. Therefore, the study does not provide sufficient evidence to conclude that forced expiratory volume differs by vaping frequency. Finally, the absence of a control group limits the ability to attribute any observed changes to vaping.

“This is an important research area. However, as the authors acknowledge, findings are preliminary. Replication is required with larger studies, appropriate control groups, and longer follow-up before reliable and meaningful conclusions can be drawn.”

Prof Lion Shahab, Professor of Health Psychology and Co-Director of the UCL Tobacco and Alcohol Research Group, University College London (UCL), said:

“In this study, researchers measured lung function in 22 people who vape, first at the start of the study and again about a year later. Some measures appeared to change over that time. The authors suggest that prolonged e-cigarette use may worsen lung function in adults. A year of follow-up is a strength, but several problems make that conclusion premature.

“First, the study had no comparison group of similar people who neither smoke nor vape. Lung function changes with age and generally declines later in adulthood. Without a comparison group, it is hard to tell whether the changes were linked to vaping or would have happened anyway. Moving home, changing jobs or stopping regular exercise could also affect lung function, and the study did not account for those changes.

“Second, participants did not have to be lifelong non-smokers. They could have smoked up to five cigarettes in the previous month. Past or recent smoking could therefore have contributed to any changes in lung function.

“Third, the study relied on a small group of volunteers, so it is hard to know whether the findings apply to people who vape more broadly or what drove the changes. With so few participants, the researchers could not tell whether the type of vape, or the contents of the e-liquid made a difference.

“Fourth, the concern is that vaping might contribute to lung disease, including COPD and emphysema. The study found no clear change in the FEV₁/FVC ratio, the standard breathing-test measure used to check for airflow obstruction in COPD.

“Fifth, the size of the reported changes is hard to explain biologically. The study reports a drop of about 100 mL over a year in FEV₁, the amount of air a person can force out in one second. For comparison, a large population study estimated annual declines at age 57 of about 31 mL in people who had never smoked and 40 mL in current smokers (1). If the whole drop were due to vaping, it would be more than twice the annual decline reported for current smokers in that study. An effect of that size is hard to square with the lack of a clear, large rise in respiratory disease among people who vape and have never smoked.

“Sixth, even setting aside the size of the drop, testing several measures creates more opportunities for a result to look significant by chance. A false positive of this kind is known as a Type I error. A standard adjustment for multiple testing, such as controlling the false discovery rate, helps account for this. After that adjustment, neither of the two FEV₁ findings remained statistically significant. Chance therefore remains a plausible explanation for the unusually large changes reported.

“Taken together, these limitations make it hard to draw firm conclusions about the impact of vaping on lung health. It is still important to investigate, because substances we inhale can affect the lungs. We need larger, more representative studies that compare people who vape and have never smoked with matched participants who neither smoke nor vape, and track changes in lung function over a longer period.”

1 – https://pubmed.ncbi.nlm.nih.gov/31606435/

* ‘Prolonged effect of e- cigarette use on pulmonary function: A Pilot Study’ by Simanta Roy et al. was published in Tobacco Control at on Tuesday 10 November 2026

DOI: 10.1136/tc-2025-059746

Declared interests:

Dr Katie East: “I have no conflicts of interest to declare.”

Prof Lion Shahab: “No COI.”