Dr Martin Juneau, M.D., FRCP

Cardiologue, directeur de l'Observatoire de la prévention de l'Institut de Cardiologie de Montréal. Professeur titulaire de clinique, Faculté de médecine de l'Université de Montréal. / Cardiologist and Director of Prevention Watch, Montreal Heart Institute. Clinical Professor, Faculty of Medicine, University of Montreal.

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4 October 2022
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Replacing tobacco with e-cigarettes reduces the risk of cardiovascular events

Smoking is directly responsible for 8 million deaths worldwide each year, mainly from cancer (30% of all cancers are due to tobacco) and cardiovascular and respiratory diseases. There is therefore clearly nothing worse than cigarettes for health, and quitting smoking remains, by far, the best decision a person can make to reduce their risk of premature death.

In recent years, electronic cigarettes have emerged as a valid alternative to tobacco cigarettes to reduce the harmful effects of smoking on health. This approach is based on a relatively simple concept: while tobacco addiction is due to nicotine, it is rather the tobacco combustion products present in cigarette smoke that are responsible for smoking-related health problems. If we can satisfy smokers’ nicotine needs while eliminating exposure to cigarette smoke, we can therefore substantially reduce the damage to their health. This is exactly what e-cigarettes do, as these devices allow nicotine to be inhaled, but without the approximately 7,000 chemical compounds found in cigarette smoke, and therefore expose users to much lower amounts of toxins. This marked decrease in toxic molecules in e-cigarette aerosols has been confirmed by several independent bodies (Public Health England, National Academies of Sciences, Engineering, and Medicine and the Committee on Toxicity of Chemicals in Food, Consumer Products, and the Environment), and it is for this reason that organizations such as Public Health England and the Académie nationale de médecine in France strongly recommend that smokers make the transition to vaping.

Cardiovascular benefits
A study recently published in Circulation, the flagship journal of the American Heart Association, is a good illustration of the positive impact of this harm reduction approach. In this longitudinal study, approximately 32,000 American adults were followed for a period of 6 years (2013–2019) to assess the risk of cardiovascular diseases (heart attack, stroke, heart failure) in smokers compared to non-smokers, exclusive e-cigarette users, and dual users (tobacco and e-cigarette).

The researchers first observed, unsurprisingly, that smokers had a much higher risk of heart disease (almost 2 times) than non-smokers (see Figure 1).

Figure 1. Increased risk of cardiovascular disease in smokers, but not in e-cigarette users (vapers). Adapted from Berlowitz et al. (2022).

However, this increase is not observed for exclusive e-cigarette users (15% increase, statistically insignificant), consistent with two recent studies (here and here). In other words, the very strong and well-documented link between smoking and cardiovascular disease is simply not observed for vaping, confirming the much lower toxicity of these devices compared to cigarette smoke. It should, however, be mentioned that dual users (who smoke and vape) have a risk of cardiovascular disease of the same order as that of smokers, which indicates that the residual exposure to tobacco toxins, even if it is slightly reduced in these people, remains harmful and sufficient to damage the heart and blood vessels.

The superiority of e-cigarette use is also highlighted when directly comparing the risk of cardiovascular events between smokers and vapers, with a reduction of about 34% in the risk observed among exclusive vapers (Figure 2). Here again, the benefits provided by e-cigarettes are completely cancelled out in dual users, and it therefore seems clear that to be truly effective in terms of harm reduction, electronic cigarettes must be a substitute for tobacco and not simply a complement, for example to obtain a dose of nicotine when it is not possible to smoke a cigarette.

Figure 2. Decreased risk of cardiovascular disease in vapers, but not in dual users. Adapted from Berlowitz et al. (2022).

These results are extremely important, because even though we already knew that e-cigarettes were safer than tobacco cigarettes, this is the first time that we have been able to quantify the reduction in risk associated with the transition from tobacco to exclusive vaping. It goes without saying that a one-third reduction in the risk of cardiovascular events has major implications in terms of public health and should prompt governments to encourage smokers to adopt vaping to reduce their risk of chronic diseases and premature mortality.

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