E-Cigarettes Linked to Reduced Respiratory Wheezing Compared to Smoking

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Key Points:

• New Evidence: A Harm Reduction Journal study finds e-cigarettes cause significantly less respiratory wheezing than smoking, reinforcing that combustion – not nicotine – is the primary driver of harm.

• Study Overview: Researchers analyzed data from the 2017–2019 Scottish Health Survey, examining 9,000 adults aged 16 and older. Participants included 1,732 exclusive smokers, 520 exclusive e-cigarette users, and 6,748 never-users. Results were adjusted for factors such as age, sex, socioeconomic status, COPD, and secondhand smoke exposure.

• Key Findings: Wheezing was reported by 32.3 percent of smokers, 17.5 percent of vapers, and 11.4 percent of never-users. Smokers were 1.8 times more likely to report wheezing than vapers, while differences between vapers and never-users were not statistically significant.

• Dose-Response Relationship: The likelihood of wheezing increased with cigarette consumption. Moderate smokers were 85 percent more likely to wheeze than vapers, and heavy smokers had more than double the odds – indicating clear respiratory harm from combustion exposure.

• Health Implications: The findings suggest that even partial substitution with e-cigarettes could reduce respiratory symptoms among smokers and dual users.

• Supporting Research: A 2022 systematic analysis found no significant short-term lung function changes from vaping. A 2024 comparative review confirmed that while both smoking and vaping can cause airway irritation, symptoms are less severe among vapers. A 2025 review found no evidence that exclusive vaping causes serious respiratory illness in never-smokers.

• Public Health Consensus: Public Health England (2015) and the Royal College of Physicians (2016) concluded e-cigarettes are around 95 percent less harmful than smoking. A 2025 Cochrane Review found high-certainty evidence that nicotine e-cigarettes increase quit rates compared to traditional nicotine replacement therapies.

• Policy Takeaway: With over 20 million U.S. adults using e-cigarettes – mostly to quit or cut down – restricting access to these harm reduction tools would be a disservice to public health and ignore mounting scientific evidence supporting their reduced-risk potential.

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A new study provides further evidence that combustion – not nicotine – is the primary driver of respiratory harm. Published in Harm Reduction Journal, the study examined differences in respiratory wheezing among various types of tobacco and vape users. As policymakers move forward with regulating alternatives to cigarettes, it is imperative that they understand nicotine is not the main cause of smoking-related illnesses.

Using data from the 2017–2019 Scottish Health Survey, the authors analyzed 9,000 adults aged 16 years or older to assess self-reported wheezing over the past 12 months. Participants were grouped into three categories: 1,732 exclusive cigarette smokers, 520 exclusive e-cigarette users, and 6,748 never-users of either product. The analysis controlled for multiple factors including age, sex, socioeconomic status, COPD, general health, and secondhand smoke exposure.

According to the findings, 32.3 percent of cigarette smokers reported wheezing, compared to 17.5 percent of e-cigarette users and 11.4 percent of never-users. Exclusive cigarette smokers were 1.8 times more likely to report wheezing than e-cigarette users. While never-users reported lower odds of wheezing than e-cigarette users, this difference was not statistically significant.

The study also found a clear relationship between smoking intensity and wheezing. Light smokers (fewer than 10 cigarettes per day) had slightly higher odds of wheezing than vapers, but the difference was not statistically significant after adjusting for demographics. Moderate smokers (10–19 cigarettes per day) were significantly more likely to report wheezing compared to e-cigarette users – an 85 percent increase in odds. Heavy smokers (20 or more cigarettes per day) had the highest risk, with more than double the odds of reporting wheezing compared to exclusive e-cigarette users. These findings indicate a clear gradient: as cigarette consumption increases from light to heavy, the likelihood of wheezing rises proportionately. This is significant for the growing population of adult dual users – those who both smoke and vape – as it suggests potential health benefits when smokers reduce daily cigarette use by substituting with e-cigarettes.

While more longitudinal studies are needed to expand upon these findings, the authors conclude that the “clear dose-response relationship observed across smoking intensity reinforces the strong respiratory burden associated with tobacco use.”

This research adds to decades of evidence showing that e-cigarettes are significantly less harmful than combustible cigarettes and may help reduce smoking-related symptoms and illnesses.

A 2022 systematic analysis comparing e-cigarette use with traditional smoking and non-use found no significant changes in most lung function measures in the short term (within one month) and no statistically significant changes in studies lasting one to three months. The authors concluded that combustion-free nicotine delivery appears less harmful than combustible smoke for pulmonary health.

Similarly, a 2024 comparative review examined the health and safety profiles of e-cigarettes versus combustible cigarettes – including respiratory effects – and found that while both smoking and vaping may cause airway irritation, coughing, and wheezing, these symptoms were less severe in e-cigarette users.

A 2025 systematic review on respiratory effects among never-smokers found no evidence that exclusive vaping causes serious respiratory illness. Some studies noted minor symptoms such as coughing and wheezing, but these were inconsistently observed.

The latest findings reinforce that e-cigarettes are less harmful than combustible cigarettes, a conclusion supported by numerous public health organizations. In 2015, Public Health England found e-cigarettes to be 95 percent less harmful than combustible cigarettes, and a 2016 Royal College of Physicians review estimated that vaping causes about 5 percent of the harm associated with smoking. Moreover, e-cigarette use is linked to higher smoking cessation rates compared to traditional nicotine replacement therapies. A 2025 Cochrane review found “high-certainty evidence that [e-cigarettes] with nicotine increase quit rates” compared to conventional cessation tools.

As of 2023, more than 20 million U.S. adults aged 18 years or older were current e-cigarette users – many of whom use them to quit smoking or gradually reduce cigarette intake. As a tobacco harm reduction tool, it is essential that policymakers understand the growing body of evidence supporting e-cigarettes as both an effective cessation aid and a reduced-risk alternative to smoking. Policies that restrict or ban access to these harm reduction tools would represent a disservice to public health.

Nothing in this analysis is intended to influence the passage of legislation, and it does not necessarily represent the views of Tobacco Harm Reduction 101.