Smokers Who Switch Completely To E-Cigs Reduce Their Exposure to Toxins Interview with:
Dr Lion Shahab
Senior Lecturer in Health Psychology
Department of Behavioural Science and Health
University College London
London What is the background for this study? What are the main findings?

Response: To date most studies on e-cigs have either looked at the product itself, i.e. analysed vapour/aerosol or e-liquid, or investigated its effects on animal and cell models. Only very few studies have looked at actual body-level exposure in users of e-cigarettes to evaluate their safety, and this study is the first to explore this in long-term real-life users of e-cigs.

We find that compared with people who continue to smoke conventional cigarettes, those who switch over completely to using e-cigarettes long-term (1.5 years) dramatically reduce their exposure to cancer-causing chemicals to levels observed in users of nicotine replacement products like nicotine patch or gum (which are known to be safe when used long-term).

Our results also suggest that while e-cigarettes are not only safer, the amount of nicotine they provide is not noticeably different to conventional cigarettes. This can help people to stop smoking altogether by dealing with their cravings in a safer way. What should readers take away from your report?

Response: The public has been receiving very mixed signals about the safety of e-cigarettes, with some reports claiming to show that they are as harmful as smoking. These reports have been based on studies that bear little relationship to exposure of e-cigarette users in the real world.

We report the first study that has actually measured the intake of potentially harmful chemicals in e-cigarette users, and compared this with people using licensed nicotine products (e.g. nicotine patches), and cigarettes. This study should reassure smokers who are thinking of switching to an e-cigarette that if they manage to cut out cigarettes altogether, they should see a large benefit in terms of their health. What recommendations do you have for future research as a result of this study?

Response: The next step would be would be to follow smokers over a longer period of time who switch over to using e-cigarettes and measure potential harm and risks not only in relation to cancer but also lung function and cardiovascular health. Is there anything else you would like to add?

Response: None of the other authors have received funding from an e-cigarette company or any organisation acting for one. Thank you for your contribution to the community.


Shahab L, Goniewicz ML, Blount BC, Brown J, McNeill A, Alwis KU, et al. Nicotine, Carcinogen, and Toxin Exposure in Long-Term E-Cigarette and Nicotine Replacement Therapy Users: A Cross-sectional Study. Ann Intern Med. [Epub ahead of print 7 February 2017] doi: 10.7326/M16-1107

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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Last Updated on February 8, 2017 by Marie Benz MD FAAD