ENDS Respiratory System

This page will include information on vapor products and heated tobacco products.

Studies

Asthma

2020: Vaping effects on asthma: results from a web survey and clinical investigation

• Almost all of the asthmatics who previously smoked would recommend switching to e-cig, and vaping did not worsen their asthma symptoms. Furthermore, switching from tobacco smoking to e-cigs showed a significant improvement in asthma control and quality of life, not showing, in the period studied, to affect pulmonary function tests.
  • Citation: Solinas A, Paoletti G, Firinu D, Di Pino M, Tusconi M, Mura JF, Del Giacco S, Marongiu F. Vaping effects on asthma: results from a web survey and clinical investigation. Intern Emerg Med. 2020 Jun;15(4):663-671. doi: 10.1007/s11739-019-02247-5. Epub 2020 Jan 20. PMID: 31960343.

2016: Persisting long term benefits of smoking abstinence and reduction in asthmatic smokers who have switched to electronic cigarettes

• This prospective study confirms that EC use ameliorates objective and subjective asthma outcomes and shows that these beneficial effects may persist in the long term. EC use can reverse harm from tobacco smoking in asthma patients who smoke. The evidence-based notion that substitution of conventional cigarettes with EC is unlikely to raise significant respiratory concerns, can improve counseling between physicians and their asthmatic patients who are using or intend to use ECs.
  • Citation: Polosa R, Morjaria JB, Caponnetto P, Caruso M, Campagna D, Amaradio MD, Ciampi G, Russo C, Fisichella A. Persisting long term benefits of smoking abstinence and reduction in asthmatic smokers who have switched to electronic cigarettes. Discov Med. 2016 Feb;21(114):99-108. PMID: 27011045.

2015: Counseling patients with asthma and allergy about electronic cigarettes: an evidence-based approach

• Smoking cessation should be strongly encouraged in patients with asthma who smoke, and they should be offered effective personalized strategies. In addition to pharmacotherapy and behavioral support, other options should be made available to manage smokers who frequently relapse and for those who are unable or unwilling to quit. A realistic alternative is to encourage these smokers to switch to ECs, a much less harmful source of nicotine.
  • Citation: Polosa R, Campagna D. Counseling patients with asthma and allergy about electronic cigarettes: an evidence-based approach. Ann Allergy Asthma Immunol. 2016;116(2):106-108. doi:10.1016/j.anai.2015.10.012

2014: Effect of Smoking Abstinence and Reduction in Asthmatic Smokers Switching to Electronic Cigarettes: Evidence for Harm Reversal

• Here, we show for the first time improvements in asthma control, AHR and pulmonary function in asthmatic smokers who quit or dramatically reduced their tobacco consumption by switching to e-cigs.
  • Citation: Polosa R, Morjaria J, Caponnetto P, Caruso M, Strano S, Battaglia E, Russo C. Effect of smoking abstinence and reduction in asthmatic smokers switching to electronic cigarettes: evidence for harm reversal. Int J Environ Res Public Health. 2014 May 8;11(5):4965-77. doi: 10.3390/ijerph110504965. PMID: 24814944; PMCID: PMC4053879.

Lung Cancer/Lung Cancer Screening

2020: Benefits of e-cigarettes in smoking reduction and in pulmonary health among chronic smokers undergoing a lung cancer screening program at 6 months

• The study is a double-blind randomized controlled trial. Two hundred and ten smokers were randomized into three groups: nicotine e-cigarette (8 mg/mL nicotine concentration), nicotine-free e-cigarettes (placebo), and control with 1:1:1 ratio. All participants received a 3 months cessation program that included a cognitive-behavioral intervention aimed at supporting people in changing their behavior and improving motivation to quit.
• After 6 months about 20% of the entire sample stopped smoking. Participants who used e-cigarettes with nicotine smoked fewer tobacco cigarettes than any other group after 6 months.
• Our data add to the efficacy and safety of e-cigarettes in helping smokers reducing tobacco consumption and improving pulmonary health status.
• Pulmonary health, assessed with self-reported measures, clinical evaluations and the Leicester Cough Questionnaire, improved in participants who stopped smoking compared to their own baseline. Moreover, participants in this group [nicotine e-cigarettes] showed the lowest level of exhaled carbon monoxide, and the lowest level of dependence compared to the nicotine-free e-cigarette and control conditions.
  • Citation: Lucchiari C, Masiero M, Veronesi G, et al. Benefits of e-cigarettes in smoking reduction and in pulmonary health among chronic smokers undergoing a lung cancer screening program at 6 months. Addict Behav. 2020;103:106222. doi:10.1016/j.addbeh.2019.106222

2020: Cancer potencies and margin of exposure used for comparative risk assessment of heated tobacco products (HTPs) and electronic cigarettes (ECs) aerosols with cigarette smoke

• Even if they should not be considered as risk-free products, however, HTPs and ECs lead to an appreciable risk reduction in comparison to cigarettes, both for cancer and non-cancer diseases. According to the current knowledge, and more specifically to the data presented here, HTPs and ECs might be considered as an acceptable reduced risk substitute for cigarettes for legal-age smokers who would otherwise continue smoking cigarettes.
• A more pronounced cancer risk reduction was observed when comparing the mean lifetime cancer risk for the considered ECs with that for cigarette smoke. This reduction was about two orders of magnitude (ratio of 0.009 and 0.014) with 2.42·10–4 and 3.95·10–4 for ECs compared to 2.73·10–2 for cigarettes. In terms of consumers, this would mean that 1 out of 36 cigarette smokers vs. 1 out of 4132 or 1 out of 2531 EC consumers may develop a cancer if the cancer root cause would be only associated with exposure to the considered HPHCs.
  • Citation: Rodrigo, G., Jaccard, G., Tafin Djoko, D. et al. Cancer potencies and margin of exposure used for comparative risk assessment of heated tobacco products and electronic cigarettes aerosols with cigarette smoke. Arch Toxicol 95, 283–298 (2021). https://doi.org/10.1007/s00204-020-02924-x

2018 Measurements of electronic cigarette-generated particles for the evaluation of lung cancer risk of active and passive users

• In this study, we have demonstrated that no clinically relevant, product-related safety findings were observed for smokers of Combustible Cigarettes (CC) switching to an Electronic Vapor Product (EVP) for 12 weeks under real-life settings. Adverse Effects (AEs) reported by subjects switching to the EVP occurred primarily within the first week after switching, and only 1.3% of all AEs reported were considered to be almost definitely related to the product. Up to a third of all reported AEs in the EVP group were related to nicotine withdrawal symptoms, which were observed to decrease after the first two weeks from product switch. EVP use was associated with significant decreases in exposure to nicotine and other chemicals such as benzene and acrolein, typically found in CC smoke. Changes were also observed in the level of WBC, haemoglobin, RBC and LDL cholesterol, which although minor, were consistent with those observed after smoking cessation. The data presented in this study shows the potential that EVPs may offer to smokers looking for an alternative to CCs.
  • Citation: Scungio M, Stabile L, Buonanno G. Measurements of electronic cigarette-generated particles for the evaluation of lung cancer risk of active and passive users. J Aerosol Sci. 2018;115:1-11. doi:10.1016/j.jaerosci.2017.10.006

2017: Reduced biological effect of e-cigarette aerosol compared to cigarette smoke evaluated in vitro using normalized nicotine dose and RNA-seq-based toxicogenomics

• Here, we assessed the transcriptional response of a primary 3D airway model acutely exposed to e-cigarette aerosol and cigarette (3R4F) smoke.
• Based on equivalent or higher nicotine delivery, an acute exposure to e-cigarette aerosol had a reduced impact on gene expression compared to 3R4F smoke exposure in vitro.
• Therefore, we can conclude that the data strongly supports the adverse effect of acute exposure to cigarette smoke on MucilAir™ cells with functional enrichment for cancer, inflammation and fibrosis genes. In contrast, RNA-seq-based toxicogenomics showed a reduced impact of e-cigarette aerosols acute exposure on MucilAir™ cells compared with 3R4F reference cigarette at equivalent or higher dose of nicotine exposure.
  • Citation: Haswell LE, Baxter A, Banerjee A, Verrastro I, Mushonganono J, Adamson J, Thorne D, Gaça M, Minet E. Reduced biological effect of e-cigarette aerosol compared to cigarette smoke evaluated in vitro using normalized nicotine dose and RNA-seq-based toxicogenomics. Sci Rep. 2017 Apr 18;7(1):888. doi: 10.1038/s41598-017-00852-y. PMID: 28420881; PMCID: PMC5429854.

2017: Comparing the cancer potencies of emissions from vapourised nicotine products including e-cigarettes with those of tobacco smoke

• “Most e-cigarette analyses indicate cancer potencies <1% that of tobacco smoke and <10% that of a heat-not-burn prototype, although a minority of analyses indicate higher potencies.”
• Optimal combinations of device settings, liquid formulation and vaping behaviour normally result in e-cigarette emissions with much less carcinogenic potency than tobacco smoke.
• Article in Lung Disease News: E-Cigarettes Carry Much Less Risk of Lung Cancer Than Cigarette Smoke, Study Finds
  • Citation: Stephens WE. Comparing the cancer potencies of emissions from vapourised nicotine products including e-cigarettes with those of tobacco smoke. Tob Control. 2018;27(1):10-20. doi:10.1136/tobaccocontrol-2017-053808

2017: Have combustible cigarettes met their match? The nicotine delivery profiles and harmful constituent exposures of second-generation (G2) and third-generation (G3) electronic cigarette users

• While not harmless, electronic cigarettes (e-cigarettes) have demonstrated a much more favourable toxicological profile than combustible cigarettes—the worldwide leading cause of preventable death. Average eCO levels (ppm) were significantly higher in smokers than in e-cigarette users. Compared with cigarettes, G2 and G3 e-cigarettes resulted in significantly lower levels of exposure to a potent lung carcinogen and cardiovascular toxicant.
  • Citation: Wagener TL, Floyd EL, Stepanov I, et al. Have combustible cigarettes met their match? The nicotine delivery profiles and harmful constituent exposures of second-generation and third-generation electronic cigarette users. Tob Control. 2017;26(e1):e23-e28. doi:10.1136/tobaccocontrol-2016-053041

2016: Patients with lung cancer: Are electronic cigarettes harmful or useful?

• Based on current knowledge, for patients with lung or other forms of cancer who would otherwise continue to smoke, e-cigarettes offer an alternative way to quit smoking while they undergo medical treatment. The option to switch to e-cigarettes should be considered by healthcare practitioners with patients with cancer who would otherwise continue to smoke.
  • Citation: Dautzenberg B, Garelik D. Patients with lung cancer: are electronic cigarettes harmful or useful? Lung Cancer. 2017;105:42-48. doi:10.1016/j.lungcan.2016.05.011

2012: Comparison of the effects of e-cigarette vapor and cigarette smoke on indoor air quality

• Comparisons of pollutant concentrations were made between e-cigarette vapor and tobacco smoke samples. Pollutants included VOCs, carbonyls, PAHs, nicotine, TSNAs, and glycols.
• Non-cancer risk analysis revealed “No Significant Risk” of harm to human health for vapor samples from e-liquids.
• With regard to cancer risk analysis, no vapor sample from e-liquids exceeded the risk limit for either children or adults.
  • Citations: McAuley TR, Hopke PK, Zhao J, Babaian S. Comparison of the effects of e-cigarette vapor and cigarette smoke on indoor air quality. Inhal Toxicol. 2012;24(12):850-857. doi:10.3109/08958378.2012.724728

General

2026: Vascular Health After Quitting Smoking or Switching to E-Cigarette Use: A Systematic Review of Prospective Studies with GRADE Assessment

• Improvements were seen across different cessation methods, including pharmacotherapy and ECs. RCTs on ECs reported significant improvements in FMD irrespective of nicotine content, suggesting that combustion rather than nicotine may be the primary driver of vascular impairment.
  • Citation: George J, La Rosa GRM, Yu J, Capodanno D, Geraci G, Ohki T, Sequeira R, Polosa R. Vascular Health After Quitting Smoking or Switching to E-Cigarette Use: A Systematic Review of Prospective Studies with GRADE Assessment. Eur J Prev Cardiol. 2026 Feb 24:zwag123. doi: 10.1093/eurjpc/zwag123. Epub ahead of print. PMID: 41735796.

2026: Adverse symptoms attributed to e-cigarettes over 6 months among participants of a randomized controlled trial testing nicotine free-base e-cigarettes for smoking cessation: secondary analysis of the ESTxENDS trial

• Among participants exclusively using e-cigarettes during a smoking-cessation trial, cough, throat irritation and dry mouth were reported most frequently during the first week and became less common over six months. The findings suggest that many symptoms attributed to switching may diminish with continued use, although some participants continued to experience irritation.
  • Citation: Güttinger E, Mosimann A, Tal K, Schoeni A, Jacot-Sadowski I, Humair JP, Pohle S, Frei A, Netzer S, Berthet A, Baggio S, Auer R, Jakob J. Adverse symptoms attributed to e-cigarettes over six months among participants of a randomized controlled trial testing nicotine freebase e-cigarettes for smoking cessation - Secondary analysis of the ESTxENDS trial. Nicotine Tob Res. 2026 Feb 20:ntag038. doi: 10.1093/ntr/ntag038. Epub ahead of print. PMID: 41717789.

2025: Differences in respiratory wheezing between current exclusive e-cigarette users, current exclusive cigarette smokers, and never users of either product: findings from a population-based study

• Exclusive e-cigarette use was not associated with higher odds of wheezing compared with never-use, and it was linked to substantially lower odds than exclusive cigarette smoking. These findings suggest that, while complete abstinence remains the lowest-risk option, e-cigarette use may pose fewer respiratory symptoms than smoking, particularly for moderate-to-heavy smokers.
  • Citation: Adebisi YA, Alshahrani NZ, Spicuzza L, Pennisi F, Geraci G, Cantone GG, Tomaselli V, Polosa R. Differences in respiratory wheezing between current exclusive e-cigarette users, current exclusive cigarette smokers, and never users of either product: findings from a population-based study. Harm Reduct J. 2025 Oct 3;22(1):156. doi: 10.1186/s12954-025-01315-8. PMID: 41044759; PMCID: PMC12495708.

2025: Association between electronic cigarette use and respiratory outcomes among people with no established smoking history: a comprehensive review and critical appraisal

• All but one study lacked clear and statistically significant evidence of self-reported respiratory diagnoses associated with EC use among PWNS, or showed a tenuous association with mild respiratory symptoms. This has favorable implications for ECs’ population health impact; however, small sample sizes and statistical biases limit this evidence. A formal systematic review on this topic is forthcoming.
  • Citation: Selya A, La Rosa GRM, Spicuzza L, Morjaria JB, Caci G, Polosa R. Association between electronic cigarette use and respiratory outcomes among people with no established smoking history: a comprehensive review and critical appraisal. Intern Emerg Med. 2025 Apr;20(3):667-680. doi: 10.1007/s11739-025-03894-7. Epub 2025 Feb 24. PMID: 39992483; PMCID: PMC12009221.

2025: Improved aerobic capacity in a randomized controlled trial of noncombustible nicotine and tobacco products

• Rapid improvements in V̇O2max can happen when healthy smokers switch to exclusive use of ECs or HTPs. These findings reinforce the potential cardiorespiratory benefits of smoking cessation and harm reduction strategies.
  • Citation: Spicuzza L, Pennisi F, Caci G, Cibella F, Campagna D, Adebisi YA, Saitta C, George J, Geraci G, Polosa R. Improved aerobic capacity in a randomized controlled trial of noncombustible nicotine and tobacco products. Sci Rep. 2025 May 31;15(1):19104. doi: 10.1038/s41598-025-03904-w. PMID: 40447739; PMCID: PMC12125353.

2025: Respiratory effects of electronic cigarette use in individuals who never smoked: A systematic review

• This systematic review and qualitative synthesis indicate that EC use among never-smoking individuals may pose mild risks of coughing and wheezing, but evidence is lacking for more significant or clinically meaningful respiratory symptoms or harms over the short to medium term (∼1–5 years). Due to the limitations of available data, ongoing research on long-term and heavy EC use is warranted to monitor respiratory risks, especially research using larger and longer-term prospective studies,and assessing more detailed EC use patterns.
  • Citation: Caci G, Selya A, La Rosa GRM, Spicuzza L, Morjaria JB, Geraci G, Polosa R. Respiratory effects of electronic cigarette use in individuals who never smoked: A systematic review. Clin Med (Lond). 2025 Mar;25(2):100295. doi: 10.1016/j.clinme.2025.100295. Epub 2025 Feb 23. PMID: 39993529; PMCID: PMC11930579.

2025: The association between e-cigarette use among Chinese college students and lung function and physical activity: A cross-sectional study

• Physical activity levels remained comparable between groups across multiple assessment domains.
  • Citation: Wang D. The association between e-cigarette use among Chinese college students and lung function and physical activity: A cross-sectional study. Tob Induc Dis. 2025 Dec 20;23. doi: 10.18332/tid/213718. PMID: 41424769; PMCID: PMC12717944.

2025: Caution required in interpreting inflammatory effects of e-cigarette use: correcting methodological and conceptual weaknesse

• Consequently, although several findings reached statistical significance, their clinical relevance remains highly questionable. Greater emphasis should have been placed on the modest magnitude of the observed changes, contextualized against baseline variability, residual effects of prior smoking, and existing scientific literature.
• Moreover, the cross-sectional design of the study precludes any conclusions about causality. Without longitudinal follow-up, it is impossible to discern whether the biomarker changes are transient or persistent—or whether they preceded the initiation of EC use. As such, attributing these biological signals to current EC exposure is speculative and unsupported by robust evidence.
  • Citation: Spicuzza L, Pennisi F, Campagna D. Caution required in interpreting inflammatory effects of e-cigarette use: correcting methodological and conceptual weaknesses. Respir Res. 2025 Aug 4;26(1):256. doi: 10.1186/s12931-025-03328-0. PMID: 40760707; PMCID: PMC12323231.

2025: Patterns of Use of e-Cigarettes and Their Respiratory Effects: A Critical Umbrella Review

• The findings of the 5 high and moderate quality systematic reviews displayed a remarkable consensus: that regardless of the pattern of use, EC use did not result in a statistically significant or clinically relevant change in respiratory function. These outcomes were based on 41 RCT or cohort primary studies, and covered a wide range of spirometry, impulse oscillometry, breath gases, and reports of serious adverse events in EC cessation trials. In considering the data in total, no clear differences in respiratory outcomes can be observed between the 3 patterns of EC use: dual use, exclusive use, or naïve use. The 5 systematic reviews in our analysis concluded that there is no definitive evidence of harm or benefit regardless of the pattern of EC use.
• One of the major limitations discussed by the systematic review authors was the lack of relevant studies. All of the 5 review teams included in our data synthesis bemoaned the lack of data.
  • Citation: Maria La Rosa, G. R., & Polosa, R. (2025). Patterns of Use of e-Cigarettes and Their Respiratory Effects: A Critical Umbrella Review. Tobacco Use Insights. https://doi.org/10.1177_1179173X251325421

2025: Evidence update on the respiratory health effects of vaping e-cigarettes: A systematic review and meta-analysis

• We observed several methodological challenges and research gaps in the included studies, which need further attention. For example, several studies defined their population as current vapers, without clearly distinguishing amongst non-smoker current vapers, former smoker current vapers and dual users. It might be inappropriate and misinformative to the audience to indicate risk of respiratory effects in current vapers, whereas this effect might be from smoking cigarettes rather than e-cigarettes. In addition, while it is important to examine effect of e-cigarette exposure among non-smoker current vapers, it is equally important to understand the magnitude of effects in former smoker current vapers and dual users compared to non-vaper current smokers.
  • Citation: Kundu, A., Feore, A., Abu-Zarour, N., Sanchez, S., Sutton, M., Sachdeva, K., Seth, S., Schwartz, R., & Chaiton, M. (2025). Evidence update on the respiratory health effects of vaping e-cigarettes: A systematic review and meta-analysis. Tobacco Induced Diseases, 23, 10.18332/tid/209954. https://doi.org/10.18332/tid/209954

2024: The association of vaping and electronic cigarette use with postoperative hypoxemia and respiratory complications: a retrospective cohort analysis

• Conclusion: Vaping/e-cigarette use was neither associated with clinically significant hypoxemia during the first hour in the postanesthesia care unit nor with an increase in pulmonary complications.
  • Citation: Saab R, Rivas E, Yalcin EK, Chen L, Montalvo M, Almonacid-Cardenas F, Shah K, Ruetzler K, Turan A. The association of vaping and electronic cigarette use with postoperative hypoxemia and respiratory complications: a retrospective cohort analysis. Can J Anaesth. 2024 Aug 7. English. doi: 10.1007/s12630-024-02801-6. Epub ahead of print. PMID: 39112772.

2024: Functionally important respiratory symptoms and continued cigarette use versus e-cigarette switching: population assessment of tobacco and health study waves 2-6

• Switching completely from past 30-day use of cigarettes to e-cigarettes had short-term beneficial associations with functionally important respiratory symptoms similar to quitting tobacco completely.
  • Citation: Sargent JD, Lauten K, Edwards KC, et al. Functionally important respiratory symptoms and continued cigarette use versus e-cigarette switching: population assessment of tobacco and health study waves 2-6. eClinicalMedicine. 2025;79:102951. doi:10.1016/j.eclinm.2024.102951

2021: Effect of an electronic nicotine delivery system with 0, 8, or 36 mg/mL liquid nicotine versus a cigarette substitute on tobacco-related toxicant exposure: a four-arm, parallel-group, randomised, controlled trial

• Use of an ENDS with cigarette-like nicotine delivery can reduce exposure to a major pulmonary carcinogen, NNAL, even with concurrent smoking.
  • Citation: Cobb CO, Foulds J, Yen MS, et al. Effect of an electronic nicotine delivery system with 0, 8, or 36 mg/mL liquid nicotine versus a cigarette substitute on tobacco-related toxicant exposure: a four-arm, parallel-group, randomised, controlled trial. Lancet Respir Med. 2021;9(8):840-850. doi:10.1016/S2213-2600(21)00022-9

2021: Impact of exclusive e-cigarettes and heated tobacco products use on muco-ciliary clearance

• Tobacco smoking impairs mucociliary clearance (MCC) efficiency as shown by prolonged saccharin test transit time (STTT). Avoiding exposure to tobacco smoke from combustible cigarettes may restore MCC function and former smokers have been shown to exhibit similar STTT as never smokers.
• Former smokers who have switched to exclusive regular use of combustion-free nicotine delivery systems (i.e., ECs and HTPs) exhibit similar saccharin transit time as never and former smokers. This suggests that combustion-free nicotine delivery technologies are unlikely to have detrimental effects on MCC function.
  • Citation: Polosa R, Emma R, Cibella F, Caruso M, Conte G, Benfatto F, Ferlito S, Gulino A, Malerba M, Caponnetto P. Impact of exclusive e-cigarettes and heated tobacco products use on muco-ciliary clearance. Ther Adv Chronic Dis. 2021 Aug 12;12:20406223211035267. doi: 10.1177/20406223211035267. PMID: 34422253; PMCID: PMC8371723.

2020: E-Cigarettes and Respiratory Disease: A Replication, Extension, and Future Directions

• The statistical associations between e-cigarette use and respiratory disease are driven by e-cigarette users who are also current or former smokers of combustible tobacco.
• A striking feature of the data is that almost all e-cigarette users were either current or former smokers of combustible tobacco.
• Among respondents who had never smoked combustible tobacco, we find no evidence that current or former e-cigarette use is associated with respiratory disease.
• Link to PDF
  • Citation: Kenkel DS, Mathios AD, Wang H. E-Cigarettes and Respiratory Disease: A Replication, Extension, and Future Directions. National Bureau of Economic Research; 2020. Working Paper 27507. doi:10.3386/w27507

2020: Exclusive e-cigarette users report lower levels of respiratory symptoms relative to dual e-cigarette and cigarette users

• Findings suggest that differences in respiratory symptoms between dual and exclusive e-cigarette users appear to be attributable to combustible cigarette smoking, rather than more intense or frequent e-cigarette use across groups.
  • Citation: Rachel N Cassidy, Jennifer W Tidey, Suzanne M Colby, Exclusive E-Cigarette Users Report Lower Levels of Respiratory Symptoms Relative to Dual E-Cigarette and Cigarette Users, Nicotine & Tobacco Research, Volume 22, Issue Supplement_1, December 2020, Pages S54–S60, https://doi.org/10.1093/ntr/ntaa150

2020: Investigation on the antibacterial activity of electronic cigarette liquids (ECLs): a proof of concept study

• Our results have shown that flavors considerably enhance antibacterial activity.
• This study provides important evidence that should be taken into consideration in further investigative approaches, to clarify the different sensitivity of the various bacterial species to e-liquids, including the respiratory microbiota, to highlight the possible role of flavors and nicotine.
  • Citation: Fuochi V, Caruso M, Emma R, Stivala A, Polosa R, Distefano A, Furneri PM. Investigation on the Antibacterial Activity of Electronic Cigarette Liquids (ECLs): A Proof of Concept Study. Curr Pharm Biotechnol. 2021;22(7):983-994. doi: 10.2174/1389201021666200903121624. PMID: 32881666.

2020: SACCHARIN TRANSIT TIME IN EXCLUSIVE E-CIGARETTES AND HEATED TOBACCO PRODUCTS USERS: A CROSS-SECTIONAL STUDY

• Ex-smokers who have switched to exclusive regular use of combustion-free nicotine delivery systems (i.e. ECs/e-cigarettes and HTPs/heated tobacco products) exhibit similar saccharin transit time as never and former smokers. This suggests that combustion-free nicotine delivery technologies are unlikely to have detrimental effects on MCC (mucociliary clearance) function
  • Citation: Polosa R, Emma R, Cibella F, et al. Saccharin transit time in exclusive e-cigarettes and heated tobacco products users: a cross-sectional study. medRxiv. Preprint published online October 23, 2020. doi:10.1101/2020.10.21.20216630

2019: A Randomized Trial of E-Cigarettes versus Nicotine-Replacement Therapy

• The e-cigarette group reported greater declines in the incidence of cough and phlegm production from baseline to 52 weeks than did the nicotine-replacement group (relative risk for cough, 0.8; 95% CI, 0.6 to 0.9; relative risk for phlegm, 0.7; 95% CI, 0.6 to 0.9). There were no significant between-group differences in the incidence of wheezing or shortness of breath.
  • Citation: Hajek P, Phillips-Waller A, Przulj D, Pesola F, Myers Smith K, Bisal N, Li J, Parrott S, Sasieni P, Dawkins L, Ross L, Goniewicz M, Wu Q, McRobbie HJ. A Randomized Trial of E-Cigarettes versus Nicotine-Replacement Therapy. N Engl J Med. 2019 Feb 14;380(7):629-637. doi: 10.1056/NEJMoa1808779. Epub 2019 Jan 30. PMID: 30699054.

2019: The effect of e-cigarette aerosol emissions on respiratory health: a narrative review.

• Expert opinion: There is growing evidence to support the relative safety of E-Cigarette (EC) emission aerosols for the respiratory tract compared to tobacco smoke. Public Health England estimated, on the basis of a review of 185 studies, that vaping an e-cigarette is likely to be at least 95% less harmful than smoking a regular cigarette. In 2016, the Royal College of Physicians reaffirmed this figure, estimating the risk of long-term inhalation of e-cigarette aerosol to be unlikely to exceed 5% of the risk associated with long-term cigarette smoking. This review article shows that although some potential effects on respiratory cell types can be shown in vitro, and low levels of chronic irritation of the respiratory tract can be anticipated at certain levels of vaping, these effects are much less than those of smoking. The clinical evidence confirms that ECs are unlikely to raise significant health concerns for the respiratory tract under normal conditions of use. Former smokers using and smokers intending to use ECs as a substitute for smoking should receive correct information about residual risks and potential benefits of these products. Promoting further access to ECs may offer an opportunity to reduce or prevent some of the otherwise inevitable burden of respiratory morbidity and mortality caused by tobacco smoking
• In an Expert Review in Respiratory Medicine article published about 7 years ago [Caponnetto P, Campagna D, Papale G, et al. The emerging phenomenon of electronic cigarettes. Expert Rev Respir Med. 2012 Feb; 6(1):63–74.., we discussed several important research developments and future avenues for e-cigarette science. In the authors’ view, those expert opinions have been substantiated by the growing body of evidence. We therefore reiterate our prediction that EC use is the most effective method of substituting tobacco cigarettes for those smokers who are unable or unwilling to quit and we are now confident that current vaping products are much less harmful than conventional cigarettes as well as earlier EC designs.
  • Citation: Polosa, R., O’Leary, R., Tashkin, D., Emma, R., & Caruso, M. (2019). The effect of e-cigarette aerosol emissions on respiratory health: a narrative review. Expert Review of Respiratory Medicine, 13(9), 899–915. https://doi.org/10.1080/17476348.2019.1649146

2018: Carbon monoxide levels after inhalation from new generation heated tobacco products

• In contrast to combustible cigarettes, no eCO elevations were observed in the exhaled breath after use of the HTPs under investigation in any of the study participants.
  • Citation: Caponnetto P, Maglia M, Prosperini G, Busà B, Polosa R. Carbon monoxide levels after inhalation from new generation heated tobacco products. Respir Res. 2018 Aug 31;19(1):164. doi: 10.1186/s12931-018-0867-z. PMID: 30170593; PMCID: PMC6119326.

2017: Health impact of E-cigarettes: a prospective 3.5-year study of regular daily users who have never smoked

• In a small sample of young-adult never-smoking, daily EC users who were carefully followed for approximately 3½ years, we found no decrements in spirometric indices, development of respiratory symptoms, changes in markers of lung inflammation in exhaled air or findings of early lung damage on HRCT, when compared with a carefully matched group of never-smoking non-EC users. Even the heaviest EC users failed to exhibit any evidence of emerging lung injury as reflected in these physiologic, clinical or inflammatory measures. Moreover, no changes were noted in blood pressure or heart rate. Since the EC users who we studied were never smokers, potential confounding by inhalation of combustion products of tobacco were obviated.
  • Citation: Polosa, R., Cibella, F., Caponnetto, P. et al. Health impact of E-cigarettes: a prospective 3.5-year study of regular daily users who have never smoked. Sci Rep 7, 13825 (2017). https://doi.org/10.1038/s41598-017-14043-2

2017: Reduced biological effect of e-cigarette aerosol compared to cigarette smoke evaluated in vitro using normalized nicotine dose and RNA-seq-based toxicogenomics

• Here, we assessed the transcriptional response of a primary 3D airway model acutely exposed to e-cigarette aerosol and cigarette (3R4F) smoke.
• Based on equivalent or higher nicotine delivery, an acute exposure to e-cigarette aerosol had a reduced impact on gene expression compared to 3R4F smoke exposure in vitro.
• Therefore, we can conclude that the data strongly supports the adverse effect of acute exposure to cigarette smoke on MucilAir™ cells with functional enrichment for cancer, inflammation and fibrosis genes. In contrast, RNA-seq-based toxicogenomics showed a reduced impact of e-cigarette aerosols acute exposure on MucilAir™ cells compared with 3R4F reference cigarette at equivalent or higher dose of nicotine exposure.
  • Citation: Haswell LE, Baxter A, Banerjee A, Verrastro I, Mushonganono J, Adamson J, Thorne D, Gaça M, Minet E. Reduced biological effect of e-cigarette aerosol compared to cigarette smoke evaluated in vitro using normalized nicotine dose and RNA-seq-based toxicogenomics. Sci Rep. 2017 Apr 18;7(1):888. doi: 10.1038/s41598-017-00852-y. PMID: 28420881; PMCID: PMC5429854.

2017: Electronic cigarette vapor alters the lateral structure but not tensiometric properties of calf lung surfactant

• While both e-cigarette vapor and conventional cigarette smoke affect surfactant lateral structure, only cigarette smoke disrupts surfactant interfacial properties. The surfactant inhibitory compound in conventional cigarettes is tar, which is a product of burning and is thus absent in e-cigarette vapor.
  • Citation: Przybyla, R.J., Wright, J., Parthiban, R. et al. Electronic cigarette vapor alters the lateral structure but not tensiometric properties of calf lung surfactant. Respir Res 18, 193 (2017). https://doi.org/10.1186/s12931-017-0676-9

2016: Lung function and respiratory symptoms in a randomized smoking cessation trial of electronic cigarettes

• Smokers invited to switch to ECs who completely abstained from smoking showed steady progressive improvements in their FEF25-75% Normalization of peripheral airways function was associated with improvement in respiratory symptoms, adding to the notion that abstaining from smoking can reverse tobacco harm in the lung.
  • Citation: Cibella F, Campagna D, Caponnetto P, Amaradio MD, Caruso M, Russo C, Cockcroft DW, Polosa R. Lung function and respiratory symptoms in a randomized smoking cessation trial of electronic cigarettes. Clin Sci (Lond). 2016 Nov 1;130(21):1929-37. doi: 10.1042/CS20160268. Epub 2016 Aug 19. PMID: 27543458.

2016: Changes in breathomics from a 1‐year randomized smoking cessation trial of electronic cigarettes

• Conclusion: “Smokers invited to switch to electronic cigarettes who completely abstained from smoking showed steady progressive improvements in their exhaled breath measurements and symptom scores. FeNo and eCO normalization is highly supportive of improved respiratory health outcomes and adds to the notion that quitting from tobacco smoking can reverse harm in the lung.”
  • Citation: Polosa R, Karas L, Emma R, et al. Changes in breathomics from a 1-year randomized smoking cessation trial of electronic cigarettes. Eur J Clin Invest. 2016;46(8):698-706. doi:10.1111/eci.12651

2016: Changes in the Frequency of Airway Infections in Smokers Who Switched To Vaping: Results of an Online Survey

• The switch from smoking to vaping was associated with a reduced incidence of self-reported respiratory infections.
• Results: “Altogether 941 responses were received. Overall, 29% of responders reported no change in respiratory symptoms, 5% reported worsening, and 66% reported an improvement (95% CI=62.9-69.0).”
  • Citation: Miler JA, Mayer BM, Hajek P (2016) Changes in the Frequency of Airway Infections in Smokers who Switched to Vaping: Results of an Online Survey. J Addict Res Ther 7:290. doi:10.4172/2155-6105.1000290

2016: Respiratory infections and pneumonia: potential benefits of switching from smoking to Vaping

• Also, given that the propylene glycol in EC aerosols is a potent bactericidal agent, switching from smoking to regular vaping is likely to produce additional lung health benefits.
• In conclusion, smokers who quit by switching to regular ECs use can reduce risk and reverse harm from tobacco smoking.
• Innovation in the e-vapour category is likely not only to further minimise residual health risks, but also to maximise health benefits.
  • Citation: Campagna, D., Amaradio, M.D., Sands, M.F. et al. Respiratory infections and pneumonia: potential benefits of switching from smoking to vaping. pneumonia 8, 4 (2016). https://doi.org/10.1186/s41479-016-0001-2

2015: What to Advise to Respiratory Patients Intending to Use Electronic Cigarettes

• The notion that under normal vaping conditions, EC toxicology is by far less problematic than tobacco cigarette toxicology and that there are beneficial effects associated with regular EC use, particularly in respiratory patients, will improve information exchange between physicians and their respiratory patients using or intending to use ECs.
• Therefore, smoking cessation should be strongly encouraged in respiratory patients who smoke, and they should be offered effective personalized strategies. Besides pharmacotherapy and behavioral support, other options should be made available to manage smokers who frequently relapse, and for those who are unable or unwilling to quit. A realistic alternative is to encourage these smokers to switch to ECs, a much less harmful source of nicotine
  • Citation: Polosa R, Campagna D, Caponnetto P. What to advise to respiratory patients intending to use electronic cigarettes. Discov Med. 2015 Sep;20(109):155-61. PMID: 26463097.

2014: Effect of Smoking Abstinence and Reduction in Asthmatic Smokers Switching to Electronic Cigarettes: Evidence for Harm Reversal

• The e-cig may help smokers with asthma to reduce their cigarette consumption or remain abstinent and hence reduce the burden of smoking-related asthma symptoms. The positive findings observed with e-cigs allows us to advance the hypothesis that these products may be valuable for smoking cessation and/or tobacco harm reduction also in asthma patients who smoke.
• By substantially reducing number of cigarettes smoked per day and exposure to their hazardous toxicants, e-cigs may not only improve asthma symptoms and pulmonary function but may also confer an overall health advantage in smokers with asthma [13]. Therefore, e-cig use in asthmatic smokers unable or unwilling to quit should be exploited as a safer alternative approach to harm-reversal (i.e., specific reversal of asthma-related outcomes) and, in general, to harm-reduction (i.e., overall reduction of smoke-related diseases).
  • Citation: Polosa R, Morjaria J, Caponnetto P, Caruso M, Strano S, Battaglia E, Russo C. Effect of smoking abstinence and reduction in asthmatic smokers switching to electronic cigarettes: evidence for harm reversal. Int J Environ Res Public Health. 2014 May 8;11(5):4965-77. doi: 10.3390/ijerph110504965. PMID: 24814944; PMCID: PMC4053879.

Video

2021: Vaping Demystified

• Yorkshire Cancer Research - Through research and interviews with experts, we explore the truth about vaping and whether misconceptions are preventing us from reducing the largest preventable cause of cancer in Yorkshire.

2nd Hand Vapor

2022: Computational modeling method to estimate secondhand exposure potential from exhalations during e-vapor product use under various real-world scenarios

• Acetaldehyde and acrolein were not detectable after use of any of the test products.
• When these data were used as inputs to a computational room air level and non-user intake model, the ambient concentrations of exhaled nicotine and formaldehyde predicted that non-user intakes were substantially reduced for test product use compared to conventional cigarette use.
• Collectively, the results predict that room air levels and exposure of the selected analytes to non-users were relatively low and several-fold below regulatory PELs and AIHA limit under the modeled space and use conditions.
• ...room air levels of nicotine, formaldehyde, acrolein, and acetaldehyde levels were significantly below OSHA PELs or American Industrial Hygiene Association (AIHA) limit...
  • Citation: Edmiston, J.S., Rostami, A.A., Liang, Q. et al. Computational modeling method to estimate secondhand exposure potential from exhalations during e-vapor product use under various real-world scenarios. Intern Emerg Med 17, 2005–2016 (2022). https://doi.org/10.1007/s11739-022-03061-2

2020: Comparative Indoor Pollution from Glo, Iqos, and Juul, Using Traditional Combustion Cigarettes as Benchmark: Evidence from the Randomized SUR-VAPES AIR Trial

• Glo, Iqos, and Juul have significantly less intense and persistent effects on indoor pollution in comparison to combustible tobacco cigarettes.
  • Citation: Peruzzi M, Cavarretta E, Frati G, Carnevale R, Miraldi F, Biondi-Zoccai G, Sciarretta S, Versaci F, Cammalleri V, Avino P, Protano C, Vitali M. Comparative Indoor Pollution from Glo, Iqos, and Juul, Using Traditional Combustion Cigarettes as Benchmark: Evidence from the Randomized SUR-VAPES AIR Trial. Int J Environ Res Public Health. 2020 Aug 19;17(17):6029. doi: 10.3390/ijerph17176029. PMID: 32825020; PMCID: PMC7504617.

2018: Characterization of the Spatial and Temporal Dispersion Differences Between Exhaled E-Cigarette Mist and Cigarette Smoke

• For both product categories, the particle concentrations registered following each puff were in the same order of magnitude. However, for e-cigarettes the particle concentration returned rapidly to background values within seconds; for conventional cigarettes it increased with successive puffs, returning to background levels after 30–45 minutes. Unlike for the e-cigarette devices tested, such temporal variation was dependent on the room ventilation rate. Particle size measurements showed that exhaled e-cigarette particles were smaller than those emitted during smoking conventional cigarettes and evaporated almost immediately after exhalation, thus affecting the removal of particles through evaporation rather than displacement by ventilation.
  • Citation: Dainius Martuzevicius, Tadas Prasauskas, Ari Setyan, Grant O’Connell, Xavier Cahours, Rémi Julien, Stéphane Colard, Characterization of the Spatial and Temporal Dispersion Differences Between Exhaled E-Cigarette Mist and Cigarette Smoke, Nicotine & Tobacco Research, Volume 21, Issue 10, October 2019, Pages 1371–1377, https://doi.org/10.1093/ntr/nty121

2017 Evaluation of Chemical Exposures at a Vape Shop

• We collected air samples for flavoring chemicals (diacetyl, 2,3-pentanedione, 2,3-hexanedione, acetaldehyde, and acetoin), nicotine, formaldehyde, and propylene glycol.
• Concentrations of vaping-related chemicals in our air samples were below occupational exposure limits.
  • Citation: Zwack LM, LeBouf RF, Schuler CR, Couch JR. Evaluation of Chemical Exposures at a Vape Shop. National Institute for Occupational Safety and Health; 2017. Health Hazard Evaluation Report 2015-0107-3279. https://www.cdc.gov/niosh/hhe/reports/pdfs/2015-0107-3279.pdf.

2017 Dr. Michael Siegel - Vape Shop Air Sampling by California State Health Department Suggests that Second Hand Vape Exposure is Minimal

• This study, although conducted under very high exposure conditions in a small, non-ventilated vape shop with many employees and customers vaping and clouds of vapor visible, did not document any dangerous levels of exposure to any hazardous chemical. Nicotine exposure was essentially non-existent. *Formaldehyde exposure was no different than in many indoor and outdoor environments at baseline. Acetone, acetoin, other aldehydes, toluene, benzene, and xylene were not detected. Chemicals that have been associated with "popcorn lung" were also not detected by the standard method.
• This study adds to the evidence that under real-life conditions, "secondhand vaping" does not appear to pose any significant health risks.
  • Citation: Siegel M. Vape shop air sampling by California State Health Department suggests that secondhand vape exposure is minimal. The Rest of the Story: Tobacco and Alcohol News Analysis and Commentary. May 1, 2017. Accessed July 15, 2026. https://tobaccoanalysis.blogspot.com/2017/05/vape-shop-air-sampling-by-california.html

2015: A rapid method for the chromatographic analysis of volatile organic compounds in exhaled breath of tobacco cigarette and electronic cigarette smokers

• Tobacco cigarette smoke provided the samples containing highest concentrations of all compounds analyzed. Besides nicotine it contained benzene, toluene, xylenes, ethylbenzene and naphthalene in high abundance as well as other compounds such as isoprene, pent-1-ene, n-pentane, n-hexane, n-heptane and others.
• This composition was in strong contrast with that of vapor from the e-cigarettes in which all these compounds were virtually absent except nicotine
  • Citation: Marco E, Grimalt JO. A rapid method for the chromatographic analysis of volatile organic compounds in exhaled breath of tobacco cigarette and electronic cigarette smokers. J Chromatogr A. 2015 Sep 4;1410:51-9. doi: 10.1016/j.chroma.2015.07.094. Epub 2015 Jul 29. PMID: 26243705.

2014: Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks

• Threshold Limit Values (TLVs), were conducted under “worst case” assumptions about both chemical content of aerosol and liquids as well as behavior of vapers.
• There was no evidence of potential for exposures of e-cigarette users to contaminants that are associated with risk to health at a level that would warrant attention if it were an involuntary workplace exposures.
• Exposures of bystanders are likely to be orders of magnitude less, and thus pose no apparent concern.
  • Citation: Burstyn, I. Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks. BMC Public Health 14, 18 (2014). https://doi.org/10.1186/1471-2458-14-18

2012: Comparison of the effects of e-cigarette vapor and cigarette smoke on indoor air quality

• Comparisons of pollutant concentrations were made between e-cigarette vapor and tobacco smoke samples. Pollutants included VOCs, carbonyls, PAHs, nicotine, TSNAs, and glycols.
• Non-cancer risk analysis revealed “No Significant Risk” of harm to human health for vapor samples from e-liquids.
• With regard to cancer risk analysis, no vapor sample from e-liquids exceeded the risk limit for either children or adults.
  • Citation: McAuley TR, Hopke PK, Zhao J, Babaian S. Comparison of the effects of e-cigarette vapor and cigarette smoke on indoor air quality. Inhal Toxicol. 2012;24(12):850-857. doi:10.3109/08958378.2012.724728

Stigma - Lung Diseases

2022: Society of Thoracic Radiology

• STR’S COMMITMENT TO NON-STIGMATIZING LANGUAGE IN LUNG CANCER CARE
• "Whether we as chest imagers realize it or not, our very language can have a negative impact on the care for the patients we serve. As published studies continue to demonstrate, smoking-related language bias often stigmatizes our patients with a smoking history and results in suboptimal care and less than desirable clinical outcomes... Instead of a report stigmatizing the patient as a “smoker,” consider describing the patient as a “person who smokes.” Rather than a “nicotine addict,” an expression such as a “person with a nicotine dependence” attenuates the common stigmatization of these patients. One will notice these alternative descriptors utilize a person-first approach rather than a habit-based one. This approach can and should be adopted in publications, society and conference presentations as well as in daily training with residents and fellows. Ultimately, this language shift more precisely aligns itself with a core underpinning of our approach to care – respect for our patients.
  • Citation: Society of Thoracic Radiology. Inspiration: Thoracic Imaging. Winter 2022. Accessed July 15, 2026.

2022: Reducing stigma triggered by assessing smoking status among patients diagnosed with lung cancer: De-stigmatizing do and don't lessons learned from qualitative interviews

• Patients expressed clear preferences for CCPS to refrain from using judgmental labels when assessing smoking history, including a preference for questions such as “have you smoked cigarettes in the past 30 days” rather than “are you a smoker?” . This perspective is consistent with the broader clinical efforts and dissemination of resources to reduce illness-related stigma through the increased use of person-first language and other bias-free language in clinical care and research. [emphasis added]
  • Ostroff JS, Banerjee SC, Lynch K, Shen MJ, Williamson TJ, Haque N, Riley K, Hamann HA, Rigney M, Park B. Reducing stigma triggered by assessing smoking status among patients diagnosed with lung cancer: De-stigmatizing do and don't lessons learned from qualitative interviews. PEC Innov. 2022 Dec;1:100025. doi: 10.1016/j.pecinn.2022.100025. Epub 2022 Mar 4. PMID: 36865902; PMCID: PMC9977138.

2021: Great Britain: symptom awareness and attitudes to lung cancer Findings from a global study

• One in four (25%) people in the UK agreed that they have less sympathy for people with lung cancer than other forms of cancer. Globally, one in five (21%) people agreed that they have less sympathy for people with lung cancer than other forms of cancer.
  • Citation: Global Lung Cancer Coalition. Great Britain: Symptom Awareness and Attitudes to Lung Cancer: Findings from a Global Study. Global Lung Cancer Coalition; 2017. Accessed July 15, 2026.

2021: MNT investigates: How lung cancer stigma holds back research and treatment

• Drs. Carter-Harris and Williamson both encourage people to use person-first language when talking about smoking. One example of this is describing someone as “a person who formerly smoked” rather than “a former smoker.”
• “By labeling someone as a smoker, you’ve depersonalized them, and you’ve identified them by a behavior that’s stigmatized,” Dr. Carter-Harris said.
• The National Cancer Institute invested nearly $575 millionTrusted Source in breast cancer research in 2018. They invested only $350 million in lung cancer research that year. Research disparities exist in other countries as well. A global analysis found that lung cancer accounted for roughly 20% of cancer deaths but only 5.6% of cancer research output in 2013.
  • Citation: Grey H. MNT investigates: how lung cancer stigma holds back research and treatment. Medical News Today. Updated March 14, 2024. Accessed July 15, 2026.

2019: ES13.05 Stigma and Impact of Tobacco Control Policy

• The stigma reduces the funding available for lung cancer research. In the US, federal funding for lung cancer research per lung cancer death is only 15% of the funding amount for breast cancer per breast cancer death.
• In a Global Lung Cancer Coalition survey, one in five people (21%) agreed with the statement that they have less sympathy for people with lung cancer than for people with other types of cancer.
• Stigmatization of smokers has the greatest impact on the socioeconomically deprived, the disadvantaged populations. These populations have the highest prevalence of smokers and encounter the stigma of their race or disadvantage (poverty, disability, sexual preference, behavioral health etc.) in addition to the stigma associated with smoking.
• This stigmatization leads people who smoke to be less likely to seek medical care when they have symptoms, more likely to lie about their smoking, more likely to be refused access to care including curative surgery for early stage lung cancer unless they quit smoking, less likely to be offered smoking cessation help if they are uncomfortable disclosing their smoking status due to stigma and bias from their healthcare professional.
  • Citation: Kitts AB. ES13.05 Stigma and impact of tobacco control policy. J Thorac Oncol. 2019;14(10):S21-S22. doi:10.1016/j.jtho.2019.08.130

2014: Lung Cancer Stigma, Anxiety, Depression and Quality of Life

• Regardless of smoking status, lung cancer patients have reported stigmatization from clinicians, family members and friends due to strong associations between smoking and lung disease.
• The results of this study confirm our previous findings that LCS [lung cancer stigma] is positively correlated with anxiety and depression and negatively correlated with QOL [quality of life].
  • Citation: Brown Johnson CG, Brodsky JL, Cataldo JK. Lung cancer stigma, anxiety, depression, and quality of life. J Psychosoc Oncol. 2014;32(1):59-73. doi: 10.1080/07347332.2013.855963. PMID: 24428251; PMCID: PMC4634635.

2014: Let's Not Wage War on Smokers

• In 2004, a team of health scientists at Oxford interviewed 45 people with lung cancer and found that felt even more stigma than other cancer patients: Participants experienced stigma commonly felt by patients with other types of cancer, but, whether they smoked or not, they felt particularly stigmatized because the disease is so strongly associated with smoking… Some patients concealed their illness, which sometimes had adverse financial consequences or made it hard for them to gain support from other people.
  • Citation: Robb A. Let's not wage war on smokers. The New Republic. February 10, 2014. Accessed July 15, 2026.

Misinformation About Nicotine and Lung Health

2023: Electronic cigarette: what perceptions in France?

• Article: 80% of French people believe that vaping causes cancer
  • Citation: Institut National du Cancer. Cigarette électronique : quelles perceptions en France ? Published January 30, 2023. Accessed July 15, 2026.

2023: Comments RE: E-cigarette vapor exposure in utero causes long-term pulmonary effects in offspring

• Given all these shortcomings (opaqueness, unrealistic airflow and nicotine, likely overexposure of mice), the results of this study are not reliable to assess potential harms from exposure to e-cigarette aerosol.
  • Source: PubPeer

2022: TOBACCO HARM REDUCTION AND NICOTINE PERCEPTIONS

• People consume nicotine, but they die from smoking. Many consumers and doctors mistakenly believe that nicotine causes various illnesses, while it is proven that the many other toxins in smoking are the reason for them.
• 69% of smokers in France and 74% of smokers in Germany believe nicotine causes cancer.
• PDF of Report
  • Citation: Wirtz B, Chaplia M, Landl M. Tobacco Harm Reduction and Nicotine Perceptions. Consumer Choice Center; 2025. Accessed July 15, 2026.

2022: Comments RE: The association between e-cigarette use and asthma among never combustible cigarette smokers: behavioral risk factor surveillance system (BRFSS) 2016 & 2017

• "The study by Osei et al. used the Behavioral Risk Factor Surveillance Survey, which contains no information about when participants started to smoke or vape, or when they were diagnosed with any disease. Therefore, it is deficient and unreliable."
  • Source: PubPeer

2022: Comments RE: E-cigarette use and respiratory symptoms in residents of the United States: A BRFSS report

• "The problem with these studies is disentangling the effects of a smoking career (something more complicated than adjusting for current-, former-, never-smoking status) and subsequent vaping behaviour. Also, the relationships are complicated by reverse causation (was the vaping a response to smoking-induced respiratory symptoms?), a hard-to-define counterfactual (has the vaping displaced smoking or displaced abstinence?), and the fact that respiratory damage arises from cumulative exposure and vaping exposures may be adding incremental risk (would the subject have any symptoms if they hadn't smoked first?)."
  • Source: PubPeer

2020: Nicotine Risk Misperception Among US Physicians

• Overall, the majority of physicians “strongly agreed” that nicotine directly contributes to the development of..., COPD (80.9%), and cancer (80.5%). ... and 30.2% did not answer this question—a potential indicator of “do not know.”
• While it is possible that some physicians may have misunderstood the question (e.g., considered harm caused by tobacco, rather than nicotine), results are consistent with other studies finding notable nicotine misperceptions.
• PDF Version
  • Citation: Steinberg, M.B., Bover Manderski, M.T., Wackowski, O.A. et al. Nicotine Risk Misperception Among US Physicians. J GEN INTERN MED 36, 3888–3890 (2021). https://doi.org/10.1007/s11606-020-06172-8
• Rutgers Article: Rutgers-Led National Survey Uncovers Doctors' Misconceptions About Nicotine Risks
• Rutgers Article: Researchers say physicians need to understand accurate nicotine risks better to assist patients addicted to the most harmful tobacco products
• Filter Article: Majority of Surveyed Doctors Misattribute Tobacco Harms to Nicotine

2020: Perceptions of nicotine in current and former users of tobacco and tobacco harm reduction products from seven countries

• PDF of full report
• ...Current consumers who agreed with the statement that nicotine is the primary cause of tobacco-related cancer ranged from 43.7% (men, UK) to 78.0% (men, SA).
• In six countries nicotine was rated nearly as harmful as cigarettes and alcohol...
• A reason why users of tobacco and THR products around the world find it hard to distinguish between the health risks of smoking and nicotine use may be due to conflicting messages from the media that deviate from the most recent scientific evidence base, overemphasize certain opinions or omit findings that do not align with their readers’ beliefs.
• We observed that the majority of current and previous product users estimated the harmfulness of nicotine and cigarettes alike. This has led to the misled conclusion that nicotine is responsible for the detrimental effects related to combustible tobacco consumption, even though science has found only very limited and often inconclusive evidence to date that nicotine is any more harmful than other legally consumed stimulants.
• Contradictory statements by leading researchers supported by renowned funding agencies and misreporting by the media may further public confusion as people have stated they use the media as a source of health information.
  • Citation: Rajkumar S, Adibah N, Paskow MJ, Erkkila BE (2020), "Perceptions of nicotine in current and former users of tobacco and tobacco harm reduction products from seven countries". Drugs and Alcohol Today, Vol. 20 No. 3 pp. 191–206, doi: https://doi.org/10.1108/DAT-04-2020-0022

2020: Comments RE: Are Electronic Cigarette Users at Risk for Lipid-mediated Lung Injury?

• "The problem is that vegetable glycerin (glycerol) is not a lipid it is an alcohol. It cannot cause the lipoid pneumonia symptoms mentioned."
• "Endogenous lipoid pneumonia from VG (or PG) inhalation is a speculation and implausible...The experience in the US over the past several months clearly shows that the culprit for the acute lung intoxication cases are black market THC oils which were sold as THC oils, not e-cigarette products."
• "visual assessment of lung HRCT scans showed no pathological findings in people vaping daily for more than 3.5 years. In particular, no CT features compatible with early signs of COPD (i.e. parenchymal micronodules, ground-glass opacity, or macroscopic emphysema) or lipoid pneumonia or popcorn lung disease were present."
  • Source: PubPeer

2019-2020: Comments RE: Association of E-Cigarette Use With Respiratory Disease Among Adults: A Longitudinal Analysis

• "One of the essential criteria of causal inference is that exposure to the cause precedes disease onset. Three of the diseases Glantz studies — COPD, chronic bronchitis and emphysema — take decades to become clinically apparent and would have been present, even though undiagnosed, in many of his cases long before his study began in 2014, and indeed even before e-cigarettes first became available in the US in about 2007. His findings are also flawed by the fact that most vapers have smoked, and since smoking is a strong cause of chronic lung disease, vapers inevitably carry an increased risk of lung disease long after quitting smoking. Glantz claims to have allowed for this statistically but his approach is simplistic: he lacks the detail of lifetime duration and intensity of smoking required. On these grounds alone his conclusion is specious."
• "Donald Kenkel and colleagues at Cornell University conducted a replication of the analysis using econometric techniques...When we use a more flexible empirical specification, among respondents who had never smoked combustible tobacco, we find no evidence that current or former e-cigarette use is associated with respiratory disease. The statistical associations between e-cigarette use and respiratory disease are driven by e-cigarette users who are also current or former smokers of combustible tobacco. A striking feature of the data is that almost all e-cigarette users were either current or former smokers of combustible tobacco."
  • Source: PubPeer

2019: Comments RE: Electronic-cigarette smoke induces lung adenocarcinoma and bladder urothelial hyperplasia in mice

• “The comparison between mice breathing vapour and mice breathing air is not statistically significant. There is no sample size justification and no power calculation. There is no message to the public here – I suspect these results are just noise.” (Britton)
• “The study has unclear relevance for human vapers. Rodents were exposed to what are for them huge concentrations of chemicals that bear no resemblance to human exposure from vaping. Several animals in fact died during these exposures. The authors assigned the effects they observed to a carcinogen NNK – but NNK has been measured before in human vapers, and it is known that exposure from vaping is either negligible or none.”

Source: Science Media Centre

2016: "Popcorn Lung" Comments RE: Comment on “Flavoring Chemicals in E-Cigarettes: Diacetyl, 2,3-Pentanedione, and Acetoin in a Sample of 51 Products, Including Fruit-, Candy-, and Cocktail-Flavored E-Cigarettes”

• • "Over the past five years, we have published the results of several studies in which diacetyl and 2,3-pentanedione levels were measured in various consumer products..."
  • "..."hundreds of consumer products (e.g., tea, coffee, citrus juices, butter) contain naturally occurring diacetyl and 2,3-pentanedione...several studies have shown that airborne diketones associated with these products are easily detectable..."
  • "Unless one assumes that unflavored coffee beans pose a serious risk of “popcorn lung,” a rare and oftentimes lethal disease, then one should agree that exposures to airborne diketone levels above the NIOSH and ACGIH OELs are not necessarily indicative of respiratory risk."
  • "Similarly, we measured concentrations of naturally occurring diacetyl and 2,3-pentanedione in mainstream cigarette smoke at levels (200–400 ppm and 30–50 ppm, respectively) that are hundreds of thousands of times higher than the NIOSH and ACGIH OELs, yet cigarette smoking is not associated with “popcorn lung”. Also, as others have noted, diketone exposures from traditional cigarettes are higher than those associated with e-cigarette use, hence switching from tobacco to e-cigarettes may result in reduced diketone exposure."
  • "Ironically, suggesting that diketone levels in e-cigarettes are potentially dangerous could actually lead to higher diketone exposures in the smoking population if smokers decide not to switch to e-cigarettes due to as yet unfounded health concerns." (Pierce, Abelmann, Finley) For further information, see authors response to the comments above.
• See Also: 2016: On the Vapor Trail: Examining the Chemical Content of E-Cigarette Flavorings
  • "The 51 e-juices sampled make up a very small proportion of all the products sold, and there is variability in the chemical content of specific products as well as how those chemicals are delivered by different devices. The authors therefore acknowledge that it is impossible to extrapolate their results to all the other products on the market. Importantly, this study did not assess levels of diacetyl, 2,3-pentanedione, and acetoin in actual users, much less health effects. So it’s premature to assume that exposure to these chemicals via e-cigarettes causes health problems."
• See Also: 2015: Is the Harvard E-Cigarette Buttery Flavor Study Credible?
  • "As I advised previously, vapers should only use liquids that are certified to be free of buttery flavors that are suspected respiratory toxicants. However, laboratory investigations of e-cigarettes should use validated methods to assure credibility. The results of the Harvard Buttery Flavor Study do not meet this standard."
• See Also: 2015: A new study finds diacetyl in e-cigarettes but exaggerates risks and fails to discuss about smoking
  • "In conclusion, the article is creating false impressions and exaggerates the potential risk from diacetyl and acetyl propionyl exposure through e-cigarettes. They failed to mention that these chemicals are present in tobacco cigarette smoke and violated a classical toxicological principle that the amount determines the toxicity and the risk."
• See Also: 2015: New Study Finds that Average Diacetyl Exposure from Vaping is 750 Times Lower than from Smoking
  • "Nevertheless, it is disingenuous and actually damaging to the public's health to spread the message that vaping causes fatal lung disease or even that it appears to increase the risk for popcorn lung. And it is especially disingenuous and damaging to send these messages to the public without telling us that smoking produces exposure to diacetyl that is on average about 750 times higher than vaping."

2016: Comments RE: Chronic electronic cigarette exposure in mice induces features of COPD in a nicotine-dependent manner

• "The mice were severely overdosed with nicotine, up to the lethal levels for mice, and a huge amount above what any human vaper would get...Regarding the relevance to human health, nicotine poisoning poses normally no risk to vapers or smokers because if nicotine concentrations start to rise above their usual moderate levels, there is an advance warning in the form of nausea which makes people stop nicotine intake long before any dangerous levels can accrue. (Mice in these types of experiments do not have that option)."
  • Source: PubPeer

2015: Comments RE: Exposure to Electronic Cigarettes Impairs Pulmonary Anti-Bacterial and Anti-Viral Defenses in a Mouse Model

• " In other words, to obtain the same exposure in humans the e-cig user should take 11000 – 13000 puffs per day. Assuming 8 hours of sleep per day, in order to acquire such a high number of puffs e-cig users would need to take 11-13 puffs per minute and thus practically take an e-cig puff with each breath. In conclusion we recommend that the results of the discussed study should be interpreted with caution and that more studies with more realistic levels of e-liquid exposure should be conducted."

2013: Survey of GPs' understanding of tobacco and nicotine products

• However, when asked to rank components of cigarettes based on their health risks, GPs ranked nicotine as the third riskiest (74 percent England, 87 percent Sweden), after tar and carbon monoxide, but before smoke or tobacco.
  • Citation: Klein A, Ramesh Patwardhan S, Murphy MA (2013), "Survey of GPs’ understanding of tobacco and nicotine products". Drugs and Alcohol Today, Vol. 13 No. 2 pp. 119–150, doi: https://doi.org/10.1108/DAT-02-2013-0010
• Article: ‘GPs falsley believe nicotine most harmful cigarette ingredient’
  • ...less than half believe that long-term nicotine replacement therapy (NRT) is preferable to smoking (31% UK, 48% Sweden).
  • Many (44% UK, 56% Sweden) also wrongly believe that nicotine in tobacco products is associated with cancer, while 15% in the UK and 22% in Sweden believe the same for pharmaceutical nicotine.
  • Citation: Nursing in Practice reporters. 'GPs falsley believe nicotine most harmful cigarette ingredient'. Nursing in Practice. June 3, 2013. Accessed July 15, 2026.

Retracted Papers

Journal Retractions

2026: Retraction: “E-cigarette use and prevalence of lung diseases among the U.S. population: a NHANES survey”

• Sage was contacted by a reader who raised concerns about the accuracy of the data the article derived from the NHANES survey results. During an internal investigation, further concerns were noted regarding authorship contribution and the number of people on the byline. We contacted the authors for comment, requesting data and calculations they derived when preparing their study’s methodology and data analysis; we also requested a detailed author contribution list that would acknowledge which specific sections each author worked on in the paper and how the individual’s subject expertise contributed to the paper.
• The author’s response to our queries did not resolve the concerns we discovered during this investigation.
• Due to our inability to verify the author contributions on the byline and the unresolved concerns we have of the accuracy of this study’s data, this article has been retracted.
• The authors did not respond when notified of this retraction.
  • Citation: Retraction: "E-cigarette use and prevalence of lung diseases among the U.S. population: a NHANES survey". J Investig Med. 2026 Aug;74(6):621. doi: 10.1177/10815589261453801. Epub 2026 May 27. PMID: 42204790.

2024: Retraction: ‘Downregulation of miR-218 by nicotine promotes cell proliferation through targeting CDK6 in non–small cell lung cancer’

• The retraction has been agreed following an investigation based on allegations raised by a third party. Several flaws and inconsistencies between results presented and experimental methods described were found. The authors were not able to provide comprehensive experimental data upon request. Accordingly, the conclusions of this article must be considered insufficiently supported.
  • Citation: (2024), Retraction: ‘Downregulation of miR-218 by nicotine promotes cell proliferation through targeting CDK6 in non–small cell lung cancer’. J Cell Biochem, 125: e30562. https://doi.org/10.1002/jcb.30562

2022: Retraction Notice to “Cancer Prevalence in E-Cigarette Users: A Retrospective Cross-Sectional NHANES Study”

• After publication of this article, concerns have been raised regarding the article’s methodology, source data processing including statistical analysis, and reliability of conclusions, the authors failed to provide justified explanations and evidence for the inquires, subsequently this article has been retracted at the request of Editor-in-Chief.
  • Citation: Editorial Office. Retraction Notice to "Cancer Prevalence in E-Cigarette Users: A Retrospective Cross-Sectional NHANES Study". World J Oncol. 2022 Dec;13(6):417. doi: 10.14740/wjon1438r. Epub 2022 Dec 24. PMID: 36660203; PMCID: PMC9822685.

2020: Retraction: "Exposure to Nicotine Containing Electronic Cigarettes Increases the Risk of Allergic Asthma in Female Offspring"

• The American Physiological Society is retracting the Articles in Press version of this article due to unresolved authorship and data concerns that were brought to our attention after publication.
  • Citation: Retraction. Am J Physiol Lung Cell Mol Physiol. 2020 Dec 1;319(6):L1061-L1061. doi: 10.1152/ajplung.00230.2019_RET.

Author Retractions

2025: Retraction Note: Exosomal miR-4466 from nicotine-activated neutrophils promotes tumor cell stemness and metabolism in lung cancer metastasis

• "The authors have retracted this article. After publication, concerns were raised regarding highly similar ex vivo brain images in Figs. 2A (Vehicle, right), 5A (miR-4466 inh., left) and 6E (-Nic.+Stat3i, right). The authors thoroughly checked the underlying data and found that the data were mismanaged, which may have affected the presented results.
  • Citation: Tyagi A, Wu SY, Sharma S, Wu K, Zhao D, Deshpande R, Singh R, Li W, Topaloglu U, Ruiz J, Watabe K. Exosomal miR-4466 from nicotine-activated neutrophils promotes tumor cell stemness and metabolism in lung cancer metastasis. Oncogene. 2022 May;41(22):3079-3092. doi: 10.1038/s41388-022-02322-w. Epub 2022 Apr 23. Retraction in: Oncogene. 2025 Jan 9. doi: 10.1038/s41388-024-03269-w. PMID: 35461327; PMCID: PMC9135627.

2021: WITHDRAWN: Smoker, Former Smoker and COVID-19: Nicotine Does Not Protect Against SARS-CoV-2

• This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause.
  • Citation: Jiménez-Ruiz CA, López-Padilla D, Alonso-Arroyo A, Aleixandre-Benavent R, Solano-Reina S, de Granda-Orive JI. WITHDRAWN: Reply to ”Smoker, Former Smoker and COVID-19: Nicotine Does Not Protect Against SARS-CoV-2”. Arch Bronconeumol (Engl Ed). 2021 Mar 16:S1579-2129(21)00082-3. doi: 10.1016/j.arbr.2021.03.012. Epub ahead of print. PMID: 33994631; PMCID: PMC7962544.