Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2025 Jun 4;26(1):207.
doi: 10.1186/s12931-025-03289-4.

Local and systemic effects in e-cigarette users compared to cigarette smokers, dual users, and non-smokers

Shanzina Iasmin Sompa  1 , Jie Ji  2 , Mizanur Rahman  2 , Bengt Sjögren  2 , Swapna Upadhyay  2 , Koustav Ganguly  2 , Anna-Carin Olin  3 , Anna Bergström  2 , Lena Palmberg  2
Affiliations
Comparative Study

Local and systemic effects in e-cigarette users compared to cigarette smokers, dual users, and non-smokers

Shanzina Iasmin Sompa et al. Respir Res. .

Abstract

Background: The use of electronic (e)-cigarettes in the long term has been associated with an increased risk of respiratory diseases. Dual use of e-cigarettes and traditional cigarettes may increase these risks even more due to the combined exposure effects of these products. The aim of this study was to investigate the local and systemic effects of e-cigarette use for more than one year and compare them with healthy non-smokers, cigarette smokers, and dual users.

Methods: The clinical study was conducted among 22 healthy non-smokers, 20 e-cigarette users, 20 cigarette smokers, and 20 dual users. Participants were matched with age and BMI, had normal baseline lung function, and had no allergies. Exhaled FeNO and bronchial responsiveness were assessed along with reactive oxygen species (ROS), toll-like receptor (TLR) expression, and inflammatory cytokines in blood and sputum.

Results: Exhaled FeNO was higher in e-cigarette users (14 ppb, p = 0.04) and lower in cigarette smokers (9 ppb, p = 0.04) compared to healthy non-smokers (11 ppb). Bronchial responsiveness was increased in e-cigarette users (1.9 mg, p = 0.01) and cigarette smokers (1.9 mg, p = 0.01) compared to healthy non-smokers (2.9 mg). ROS in blood and sputum in e-cigarette users (p = 0.005 and p = 0.04) and dual users (p = 0.003 and p = 0.04) were increased. Also, TLR2 expression in blood granulocytes in all exposed groups (p = 0.001), TLR2 and TLR4 expression in sputum in e-cigarette users (p = 0.04 and p = 0.03) and dual users (p < 0.0001 and p = 0.004) were increased. Moreover, the percentage of IL13 and IFNγ cytokine-producing T cells in blood were increased in e-cigarette users (p = 0.0001 and p < 0.0001) and dual users (p = 0.001 and p < 0.0001).

Conclusion: Our research indicates that both local and systemic inflammatory responses, along with innate immune receptor activity, were significantly altered in e-cigarette users and dual users. Notably, these alterations were detected in e-cigarette users within a short timeframe of just 1 to 3 years of use.

Clinical trial number: Not applicable.

Keywords: Cytokines; Dual use; E-cigarettes; FeNO; TLR.

PubMed Disclaimer

Conflict of interest statement

Declarations. Ethics approval and consent to participants: The study was approved by the regional ethics committee in Stockholm (reference no 2016/1220–31, 2018/2584–32 and 2021–00378) and performed in accordance with the Helsinki declaration. The participants were informed about the study design and their right to interrupt at any time during an ongoing clinical examination and sample collection procedures. A written informed consent was obtained from each participant prior to the study and documented. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Fractional nitric oxide (FeNO) levels in exhaled air, measured by NIOX VERO (A). Cumulative Provocation dose of methacholine that produces a 20% drop of FEV1 (B). Data presented as median with interquartile range. Statistical significance was tested by Kruskal-Wallis followed by the post hoc Mann-Whitney test. * p < 0.05, ** p < 0.01, *** p < 0.001
Fig. 2
Fig. 2
Total cellular reactive oxygen species (ROS) levels in the blood (A) and sputum (B), analyzed by flow cytometry. Data presented as median with interquartile range. Statistical significance was tested by Kruskal-Wallis followed by the post hoc Mann-Whitney test. * p < 0.05, ** p < 0.01
Fig. 3
Fig. 3
Surface expression of TLR2 (A– B) and TLR4 (C– D) on blood leucocytes, analyzed by flow cytometry. Data presented as median with interquartile range. Statistical significance was tested by Kruskal-Wallis followed by the post hoc Mann-Whitney test. * p < 0.05, ** p < 0.01, *** p < 0.001
Fig. 4
Fig. 4
Surface expression of TLR2 (A) and TLR4 (B) in sputum immune cells, analyzed by flow cytometry. Data presented as median with interquartile range. Statistical significance was tested by Kruskal-Wallis followed by the post hoc Mann-Whitney test. * p < 0.05, ** p < 0.01, *** p < 0.001
Fig. 5
Fig. 5
Soluble TLR2 in serum (A) and in sputum (B) supernatant measured by ELISA. Data presented as median with interquartile range. Statistical significance was tested by Kruskal-Wallis followed by the post hoc Mann-Whitney test. * p < 0.05
Fig. 6
Fig. 6
T cell cytokines profile in CD3 positive (A– B) and CD4 positive (C– D) T cells in blood, analyzed by flow cytometry. Data presented as median with interquartile range. Statistical significance was tested by Kruskal-Wallis followed by the post hoc Mann-Whitney test. * p < 0.05, ** p < 0.01, *** p < 0.001
Fig. 7
Fig. 7
The concentration of tissue injury/repair markers in serum, sputum, and saliva (A– F), measured by ELISA. Data presented as median with interquartile range. Statistical significance was tested by Kruskal-Wallis followed by the post hoc Mann-Whitney test. * p < 0.05, ** p < 0.01, *** p < 0.001
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. A Report of the Surgeon General. (2010) Pulmonary diseases - How Tobacco Smoke Causes Disease. https://www.ncbi.nlm.nih.gov/books/NBK53021/. Accessed 3 Jul 2023.
    1. FDA. (2021) How Smoking Affects Heart Health| FDA. https://www.fda.gov/tobacco-products/health-effects-tobacco-use/how-smok.... Accessed 27 Dec 2023.
    1. A Report of the Surgeon General. E-Cigarette use among youth and young adults. Centers for Disease Control and Prevention (US); 2016. - PubMed
    1. CDC. More than 2.5 million youth reported E-Cigarette use in 2022|. CDC Online Newsroom| CDC; 2022.
    1. Canistro D, Vivarelli F, Cirillo S, et al. E-cigarettes induce toxicological effects that can Raise the cancer risk. Sci Rep. 2017;2017 7(1):1–9. - PMC - PubMed

Publication types

MeSH terms

LinkOut - more resources