Two new studies, investigating the health effects of e-cigarettes, have been published. One study was reported by the media to have found that children who try e-cigarettes are more likely to start smoking tobacco, though the study provides only weak evidence for this claim. The other study reported that e-cigarettes could do more harm than good, as the number of adolescents and young adults who take up conventional smoking would be more significant than decreases in adult cigarette smokers.
The first study was based on a survey of 1,152 11 to18-year olds in the UK[i]. The participants answered questions at the start of the study, and again 4 - 6 months later. Among 923 who had never smoked at baseline, those who had tried e-cigarettes were around 12 times more likely to have tried smoking by follow-up than those who had never used e-cigarettes. However, there were only 21 people who had used an e-cigarette at baseline and started smoking cigarettes within the study, so there is a large margin of error in this finding. Further, those who increased their use of e-cigarette smoking were around 8 times more likely to have tried conventional smoking than those who did not increase their e-cigarette use. There is large uncertainty in this finding, as only 41 people were in this category. This research provides further insight into the relationship between smoking and e-cigarette use among young people, but it is important to realise that it does not provide firm evidence that people who try e-cigarettes without having smoked previously are then more likely to start smoking[ii].
In the second study, researchers quantified the balance of health benefits and harms associated with e-cigarette use in the United States. They used census data, national health and tobacco use data. Using a simulation model, it was estimated that 2,070 current cigarette smoking adults would stop smoking in 2015 due to e-cigarette use, but that 168,000 adolescents who had never smoked would become cigarette smokers through the use of e-cigarettes. Overall, the model estimated that e-cigarette use in 2014 would lead to 1,510,000 years of life lost.[iii] The lead author, Samir Soneji, says, ‘E-cigarettes will likely cause more public health harm than public health benefit unless ways can be found to substantially decrease the number of adolescents and young adults who vape and increase the number of smokers who use e-cigarettes to successfully quit smoking’.[iv]
We reported recently, in issue 217 of BC Disease News, that a report from the United States National Academies of Science, Engineering and Medicine found that, although e-cigarettes may be associated with some health risks, they are likely to be far less harmful to the user than conventional cigarettes[v]. The committee found that, among adults who smoke conventional cigarettes, use of e-cigarettes may help them to stop smoking, whereas among youth, use of e-cigarettes increases the risk of transitioning to conventional cigarette use. One of the conclusions of the report was that in order to maximize the health benefits of e-cigarettes, their use among youth should be discouraged. The findings of the new studies, regarding e-cigarette use among teenagers, are generally in agreement with this report. Even though e-cigarette use by an individual is less harmful than conventional cigarette use, at population level, e-cigarettes could be more harmful if they lead to large numbers of adolescents taking up smoking.
[i] East, K. et al. The Association Between Smoking and Electronic Cigarette Use in a Cohort of Young People. Journal of Adolescent Health 0, (2018). http://www.jahonline.org/article/S1054-139X(17)30903-5/fulltext (Accessed 16 March 2018)
[ii] ‘Weak’ evidence linking e-cigarette use with future smoking. NHS Choices Behind the Headlines, 13 March 2018. https://www.nhs.uk/news/pregnancy-and-child/weak-evidence-linking-e-cigarette-use-future-smoking/ (Accessed 16 March 2018)
[iii] Soneji, S. S., Sung, H.-Y., Primack, B. A., Pierce, J. P. & Sargent, J. D. Quantifying population-level health benefits and harms of e-cigarette use in the United States. PLOS ONE 13, e0193328 (2018). http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0193328 (Accessed 16 March 2018)
[iv] E-cigarettes may be more harmful than beneficial, according to evidence-based research. Science Daily. 14 March 2018 https://www.sciencedaily.com/releases/2018/03/180314145034.htm (Accessed 15 March 2018)
[v] National Academies of Sciences, Engineering, and Medicine. 2018. Public Health Consequences of E-Cigarettes. Washington, DC: The National Academies Press. https://doi.org/10.17226/24952 Available at https://www.nap.edu/catalog/24952/public-health-consequences-of-e-cigarettes (Accessed 29 January 2018).