- 141 regular smokers were subjected to three different treatments: 1) tobacco cigarette (control group), 2) e-cigarette containing nicotine, and 3) e-cigarette containing no nicotine.
- A month later, researchers measured arterial stiffness and dysfunction of blood vessels, two major risk factors for cardiovascular disease.
- The results show that the transition to e-cigarettes rapidly improves the function of blood vessels, regardless of its nicotine content, confirming the usefulness of these devices for reducing cardiovascular damage caused by tobacco.
A study recently published in the Journal of the American College of Cardiology confirms the enormous potential of e-cigarettes to reduce cardiovascular damage caused by combustible tobacco. In this randomized clinical study, researchers recruited 141 regular smokers (15 or more cigarettes per day for at least two years) and randomly separated them into 3 distinct groups: 1) a control group, in which participants continued to smoke tobacco cigarettes; 2) a group where participants replaced tobacco cigarettes with e-cigarettes containing nicotine (16 mg); and 3) a group where participants replaced tobacco cigarettes with e-cigarettes not containing nicotine. To measure the impact of different treatments on cardiovascular health, the researchers measured, at the start of the study and 1 month later, arterial stiffness and dysfunction of blood vessels, two important risk factors for cardiovascular disease.
This approach measured 5 major positive changes associated with the substitution of tobacco cigarettes by e-cigarettes:
1) The transition to e-cigarettes quickly improves the function of blood vessels. The function of the endothelium (the thin layer of cells lining the inside of blood vessels) was assessed by flow-mediated dilatation, a technique that measures the ability of these vessels to dilate. An increase in vasodilation allows a better supply of oxygen to peripheral tissues and is considered an excellent marker of the health of blood vessels.
The researchers observed that flow-mediated vasodilation is increased significantly only 1 month after the substitution of tobacco cigarettes by e-cigarettes, independently of the presence of nicotine (Figure 1). The increase observed (about 1.5%) may seem minimal at first glance, but several studies have shown that an increase of only 1% in flow-mediated vasodilation is associated with a 13% decrease in the risk of cardiovascular events. According to the authors, the observed vasodilation values are even close to those of healthy non-smokers, which shows how quickly the transition to e-cigarettes had beneficial effects on the cardiovascular health of smokers.
Figure 1. Change in mean flow-mediated dilatation among tobacco cigarette smokers and e-cigarette users.
2) Arterial stiffness is reduced as a result of the transition to e-cigarettes. Arterial stiffness was assessed using pulse wave velocity, a technique that measures the speed at which the pulse travels along the arteries. The stiffer the arteries, the less ability they have to contract and expand as a result of changes in blood volume and therefore the higher the speed of pulse wave propagation. A reduction in velocity should thus be considered as a sign of improved vessel health.
This is what has been observed in smokers who have smoked the equivalent of a pack of 20 cigarettes per day for less than 20 years (20 packs-years): the measurement of pulse wave velocity in these people indicates a significant decrease in artery stiffness following the transition to e-cigarettes (with or without nicotine). However, this phenomenon is not observed in smokers who have been smoking longer (>20 pack-years), which could suggest that in these people, the damage caused by tobacco to the elasticity of the arteries is more pronounced and could not be mitigated in just one month of intervention.
3) Women can particularly benefit from the transition to e-cigarettes. An analysis of the results by sex of smokers indicates that the improvement in vasodilation mediated by the flow obtained following the adoption of e-cigarettes appears to be more pronounced among women smokers than men smokers. This is very important because women who smoke are much more at risk of developing smoking-related health problems than men, with almost 3 times more risk of developing lung cancer and 2 times more risk of having a myocardial infarction. With approximately 200 million women currently smoking cigarettes worldwide, the potential for harm reduction by e-cigarettes in this population is therefore considerable.
4) The more complete the transition to e-cigarettes, the better its impact on the health of blood vessels. An easy test to determine if a person has recently smoked a tobacco cigarette is to measure the level of expired carbon monoxide (CO). The authors observed that participants with the lowest CO levels also had the strongest improvements in blood vessel function, suggesting that the positive effects observed in the study would have been even more pronounced if all smokers had used e-cigarettes exclusively. Nevertheless, the significant improvement in vessel health, even among those who “cheat” from time to time, indicates that any reduction in tobacco use, even if not total, is positive for health.
5) The presence of nicotine has no influence on the benefits of e-cigarettes. No difference in cardiovascular benefits could be observed between e-cigarettes containing nicotine or not, which is consistent with several observations showing that it is tobacco combustion products, not nicotine, that are responsible for the negative effects of smoking. Of course, nicotine is the drug that creates tobacco addiction and encourages people to smoke, but it has no major health effects and is not responsible for cardiovascular disease or lung cancer that results from smoking.
Overall, this study, which stands out from many others, must be commended for its scientific rigour and its clinical relevance. Recently, there have been many reports in the media about studies that claim to show that the vapour generated by electronic cigarettes has harmful health effects, with some going as far as to say that they are as harmful as cigarettes. What the media reports do not say, however, is that these studies often have serious methodological flaws that completely invalidate their conclusions. For example, a few days before the publication of the article described here, a summary presented at the American Heart Association’s annual conference reported that e-cigarettes had an adverse effect on blood vessel function, i.e. they decreased flow-mediated vasodilation. However, these parameters were measured immediatelyafter the inhalation of the vapour, which makes no such conclusions possible: just about anything that is stimulating (coffee, sex, alcohol or even certain foods) elicits this type of acute response in the short term, but this effect is transient and has no longer-term impact. It is only when abnormalities in blood vessel function occur over long periods of time (as in the study described earlier) that they can serve as a marker of risk of future cardiovascular events.
Another good example of disinformation about the effects of e-cigarettes is a study that claims to show an increased risk of heart attack in vapers: a close examination of the data indicates that the majority of the infarctions reported in the study occurred before the adoption of vaping by participants and therefore cannot be due to e-cigarettes! Since vapers are generally ex-smokers, the increase in infarction observed among vapers is simply due to the fact that these people have given up smoking after being sick and are now using e-cigarettes to avoid a recurrence. It is therefore appalling that this type of study, which does not even respect the basic rules of the scientific approach, is currently being used as a pretext to claim that e-cigarettes are as dangerous as tobacco cigarettes, and at the same time create a climate of mistrust towards these devices.
The main danger of the current anti-vaping climate is to reduce the number of smokers who make the leap to e-cigarettes. I can already see it in my practice: patients who had quit smoking thanks to vaping have started smoking again, while others are reluctant to try e-cigarettes. In both cases, the reason given is the same: if vaping is as bad as smoking, why make the transition? So, we can see that disinformation campaigns can have real consequences for people’s lives and even literally make the difference between life and death for some of them.
It is worth remembering that the ultimate goal of tobacco control is to reduce the incidence of smoking-related diseases, particularly cardiovascular disease and lung cancer. Although in theory total abstinence is desirable to achieve this goal (one cannot be against virtue), the reality remains that many people are unable to quit using current smoking cessation tools and therefore remain at risk of dying prematurely. The value of e-cigarettes is that they allow these people to considerably reduce their exposure to the many toxic substances of cigarette smoke, with immediate positive effects on their health. Moreover, not only are e-cigarettes less toxic than tobacco, but a randomized clinical study recently published in the prestigious New England Journal of Medicine shows that they can be very useful for smoking cessation, with twice the effectiveness of traditional nicotine substitute approaches. Instead of trying by all means to “demonize” e-cigarettes, these devices should instead be seen as a very interesting technological innovation that adds a new dimension to the fight against tobacco.
We must therefore hope that serious studies, such as the one described here, will succeed in putting an end to current disinformation campaigns and remind smokers that e-cigarettes are much less harmful than tobacco and can greatly help them quit smoking definitively.
I want to make it clear that I do not receive any compensation from companies and shops that sell e-cigarettes. I also do not receive fees as a speaker or consultant from pharmaceutical companies, especially those that make products to quit smoking, unlike many doctors and scientists who are very critical of e-cigarettes.
In recent years, there has been much mention of the marked increase in the use of e-cigarettes by young people, a trend that has recently increased with the arrival of Juul (see our article on this topic). The often alarmist tone that accompanies the reports of these studies suggests that vaping currently reaches “epidemic” proportions and poses a serious threat to the health of young people by pushing them towards the traditional cigarette.
These fears are no doubt in good faith, but they are not at all consistent with the results of the serious surveys that have been conducted in recent years, particularly with regard to smoking rates among young people.
Smoking rates continue to plummet among young people.
Very little is said about it, but one of the most encouraging trends in tobacco control is the marked decline in youth smoking seen in recent years. One of the best examples of this reduction is provided by the “Monitoring the future” survey, a large epidemiological study conducted since 1975 by researchers at the University of Michigan, which annually measures the prevalence of users of different drugs among American high school students. As shown in Figure 1, while youth smoking peaked in 1997 with 37% of 12th grade youth who smoked occasionally and 25% who smoked daily, these proportions have since significantly fallen to 7.6% and 2%, respectively, in 2018. A similar trend is observed in Canada, with approximately 3.5% of 12–17-year-olds who were smokers (casual or regular) in 2017, a 25% decrease compared to 2013 (4.6%). It should also be noted that according to the latest data from Statistics Canada, the proportion of Canadians aged 12–17 who smoked cigarettes daily was only 0.9% in 2018.
Figure 1. Changes in the proportion of smokers among 12thgrade American high school students from 1975 to present day. From Bates (2019).
Can the introduction of e-cigarettes reverse these trends, as many fear? There has been a lot of evidence from studies (here, here and here, for example) that teens who have tried e-cigarettes are more likely to smoke a tobacco cigarette than those who have never been in contact with the electronic cigarette. But as several experts have pointed out, this interpretation is not scientifically valid, because it is impossible to establish a causal link between the two phenomena: a young person attracted by tobacco will experiment with several forms available, without necessarily meaning that trying one will lead to testing another.
To determine the impact of the e-cigarette, the best measure remains to examine the evolution of youth smoking. And in this regard, the results are reassuring: although these products have appeared relatively recently (around 2010), the available data suggest that they have not had negative impacts on the adoption of cigarettes by young people: in the United States, for example, the smoking cessation rate is 3 to 4 times higher between 2010 and today than between the period from 1975 to 2010, suggesting that e-cigarettes have instead accelerated the reduction of youth smoking (Figure 1). It should also be noted that Juul has been available since 2015 in the United States and has since conquered most of the e-cigarette market, but this has not resulted in a resurgence of youth smoking. The data are also reassuring for England, where e-cigarettes have been available for several years: the smoking rate has been steadily decreasing since 2011 and the largest decrease is observed among 18–24-year-olds.
According to the data currently available, the fear that vaping leads to smoking therefore seems totally unfounded. On the contrary, it seems that vaping represents an increasingly popular alternative to traditional cigarettes and could even replace conventional tobacco products in the short and medium term. This is very encouraging, since it is clearly established that e-cigarette vapour is much less harmful than cigarette smoke, particularly because of a very significant decrease in the presence of carcinogenic compounds.
Regular vapers are usually smokers.
A recent study found that the proportion of young e-cigarette users has increased significantly in Canada from 29% to 37%. At first glance, this may actually seem enormous, and it is this type of statistic that is at the root of the concerns raised by vaping critics.
However, it is important to know that in this type of study, individuals are considered smokers or vapers if they have used these products at least once in a given period (in the last month, for example) or during their lifetime. This approach fails to distinguish occasional users from those who regularly smoke or vape. To make a simple analogy, it is as if a study of pathological gambling considered that people who buy a lottery ticket from time to time belong to the same category as those who go to the casino every day. This is obviously not the case: it is the development of a dependence on a substance (tobacco, alcohol, drugs, opiates) or an activity (excessive gambling, for example) that poses risks, whereas occasional use is much more like an experiment, a phenomenon that is particularly common among young people.
In fact, when we take into account the frequency of vaping and smoking habits, the situation is much less worrying. As shown in Figure 2, the vast majority of young people only vape occasionally (only 3.6% of 16-19-year-olds were vaping more than 15 days per month according to the latest estimates); 2) it is mainly young people who smoke cigarettes (regularly or occasionally) who are attracted to these products; and 3) only a tiny proportion of non-smokers (less than 1%) vape regularly.
Figure 2. Distribution of vapers according to the frequency and habits of tobacco use. Note the very low percentage of non-smoking youth who regularly vape (arrow). From Hammond et al. (2019).
The situation is not “out of control”, as we hear regularly, but rather reflects a new reality: the traditional cigarette is no longer popular with young people, possibly because of the exorbitant prices and smoking bans in almost all public places. The vast majority of those who want to experiment with the effect of tobacco are turning to new forms of nicotine such as e-cigarettes, but even then, regular users of these products remain relatively few, and are for the most part young people who are primarily attracted to tobacco or inclined to adopt higher-risk behaviours in general. This last point is well illustrated by a study in Colorado, where researchers have found that vapers are 5 to 10 times more likely to have previously tried hard drugs such as cocaine or regularly drink excessive amounts of alcohol than non-vapers (Table 1).
Table 1. Comparison of the prevalence of risky behaviours between vapers and non-vapers. From Ghosh et al. (2019).
Overall, and despite the sensationalist headlines in recent years, we must consider that e-cigarettes do not pose a threat to the enormous progress we have made in tobacco control. On the contrary, regular vapers are mostly smokers, and the adoption of these products can substantially reduce the risks associated with cigarette smoke. Based on the very low percentages of non-smokers who regularly vape, it also seems that nicotine vapour is less addictive than traditional cigarettes and it is very unlikely that it can be used as a gateway to tobacco.
It should also be remembered that the main utility of e-cigarettes remains one of the best ways to quit smoking, with twice the effectiveness of nicotine replacement therapy. The British have long recognized the usefulness of e-cigarettes in tobacco control and, hard to imagine here, have even made these products the emblem of anti-smoking campaigns (see photo).
(Public Health England advertising promoting e-cigarettes to quit smoking)
An extremely damaging collateral effect of the current “hysteria” towards e-cigarettes is to make smokers suspicious of these products and at the same time to deprive them of a valuable aid to quit smoking. The latest surveys also show a sharp increase in the number of smokers who think that the e-cigarette is as, if not more, damaging than the traditional cigarette. This is a very unfortunate situation, which shows how the best is sometimes the enemy of the good: by wanting at all costs to prevent vaping among young people, we are creating a climate which discourages the use of alternatives to tobacco that are infinitely less dangerous and would have a very positive impact on the health of smokers.
Of course, we must remain vigilant about the use of these products by young people and I will be the first to question the regulatory framework surrounding their marketing if it turns out that modern e-cigarettes (Juul, for example) lead to an upsurge in smoking among this population. With the current state of knowledge, on the other hand, there are many reasons to be optimistic and consider the electronic cigarette as a very promising tool to reduce smoking and even, hopefully, ultimately lead to the complete disappearance of the traditional cigarette.
For several years, I have been suggesting to my smoking patients to turn to e-cigarettes to reduce the cardiovascular risks associated with smoking. As mentioned in another article, the vaporization of a nicotine solution by these devices generates far fewer toxic compounds than burning tobacco and therefore represents a valid alternative for people who are addicted to nicotine and want to reduce the damage caused by tobacco.
Based on my clinical experience, the success rate of this approach is excellent, with approximately 70% of patients quitting, including several people who had “tried everything” before. On the other hand, these people are not really representative of the “average smoker”, either because they are very sick and absolutely must quit to continue to live, or because a cardiovascular event has given them the scare of their lives and they want to reduce the likelihood that such an event will happen again.
A randomized clinical trial, recently published in the New England Journal of Medicine, provides a clearer view of the potential of e-cigarettes among people who wish to quit,butarenot necessarilyrequiredto do sodueto illness. The researchers contacted 2,045 individuals who had approached the free smoking support services of the British National Health Service (NHS), and randomly assigned 886 of them to two types of smoking cessation protocols, either using the e-cigarette (439 participants) or the standard nicotine substitutes (patches, chewing gums, nasal or oral sprays and lozenges, alone or in combination according to the preference of smokers) (447 participants). All participants received psychological support in the form of a personalized weekly meeting with a physician throughout the study.
The results indicate that the one-year abstinence rate is 18% for e-cigarette users, nearly double that achieved with nicotine replacement therapy (9.9%) (Figure 1). According to feedback received from participants, e-cigarettes provide greater satisfaction and reduce the urgency of smoking more effectively than nicotine replacement products, particularly during the first few weeks after stopping smoking, which explains better adherence to treatment throughout the study. This superiority of the e-cigarette is particularly noteworthy since the nicotine replacement therapy used in this study can be considered optimal, i.e., participants had access to sustained psychological support as well as a wide range of distinct products that can deliver nicotine consistently (patches) or more quickly, to alleviate acute attacks caused by lack (vaporizers). With a smoking cessation rate twice as high as that obtained by nicotine substitutes, it seems that e-cigarettes are a much more effective method of quitting smoking than these products.Figure 1. Comparison of cigarette abstinence rates between users of e-cigarettes and nicotine replacement products. Adapted from Hajek et al. (2019).
These results are important because even though nicotine replacement products have been used for many years for smoking cessation, the success rate of these products remains relatively low. Pharmacological treatments with varenicline (Champix) or bupropion (Zyban) can improve this success rate, but these drugs can cause very significant side effects (especially Champix), which prevents their use on a large scale. Since the e-cigarette has a higher success rate than nicotine substitutes and is similar to varenicline (about 20%), with no significant side effects, this tool could become an essential part of tobacco control.
It is therefore to be hoped that the results of this study will change the rather negative attitude of the medical community towards e-cigarettes. Despite the large body of scientific evidence showing that these products are far less harmful to health than traditional cigarettes, the majority of tobacco control organizations continue to advise against the use of this tool to quit smoking.
This reluctance is largely due to the fear that e-cigarettes will serve as a “gateway” for young people to traditional cigarettes, thereby undermining the progress made over the last 50 years in tobacco control. This concern has reached its peak this year due to the significant increase of young e-cigarette users in the United States: between 2017 and 2018, the proportion of high school students who have used an e-cigarette in the last 30 days has increased from 11.7% to 20.8%, an increase due in large part to the huge popularity of the Juul e-cigarette (see our article on this new product). On the other hand, this increase in vaping does not appear to result in an increase in traditional cigarette use, as smoking rates among young people are stable (around 8%), a much lower proportion of smokers than 25 years ago (28.3% in 1996). These data therefore suggest that very few young non-smokers will become regular smokers as a result of experimenting with an e-cigarette and therefore this product does not appear to be a gateway to smoking.
In sum, the data currently available confirm that e-cigarettes are a valuable tool in the fight against smoking. Rather than a “gateway” to tobacco, the e-cigarette could instead be an “exit door” and it is to be hoped that the U.S. FDA will not move forward with its threat to remove e-cigarettes from the market to confront the rise of vaping among young people. It would be a disproportionate response to a hypothetical problem, but with disastrous consequences for smokers who want to quit.
Updated November 13, 2018
Marketed in 2015, the Juul (pronounced “jewel”) quickly became the most popular electronic cigarette in the United States and currently accounts for 70% of market shares. The recent arrival of Juul in Canada (September 2018) is a good opportunity to describe this new product, presented by its manufacturer as a smoking cessation aid.
The first feature of Juul that stands out is its elegant design: measuring 9.4 cm long, 1.5 cm wide and 0.8 cm thick (for a total weight of just 10 g), the product looks much more like a USB key than an electronic cigarette. In addition to its beautiful appearance, the Juul is also extremely easy to use: simply insert a cartridge (called “pod”) at the top of the device and suck the steam generated by the device, without having to handle liquid or operate additional buttons. Each cartridge contains 0.7 mL of a solution of propylene glycol, glycerine, artificial flavours and 5% nicotine, which is roughly the amount in a pack of cigarettes.
The main innovation brought by Juul, however, remains its ability to reproduce the amount of nicotine that is absorbed when using traditional combustible cigarettes. As shown in Figure 1, blood levels of nicotine measured after a puff of Juul-generated steam are very similar to those with a traditional cigarette and much higher than with most other e-cigarettes available on the market.
Figure 1. Comparison of the amount of nicotine absorbed after a puff of different forms of cigarettes.
Nicotine salts vs. free nicotine
The key to understanding the superiority of Juul lies in the chemistry of the nicotine molecule. In its natural state, nicotine is a weak base that associates spontaneously with an acid to form salts (monobasic and dibasic) (see figure opposite).
These nicotine salts are not very volatile and are therefore poorly absorbed by the lungs when smoking tobacco; however, in the 1960s, chemists working at the tobacco company Philip Morris discovered that if tobacco is treated with an alkaline solution (e.g., ammonia-based), nicotine is converted to a much more volatile free base (more than 100 times), which greatly increases its absorption in the lungs and brain. This was a major breakthrough because, by secretly manipulating the bioavailability of tobacco nicotine, cigarettes became much more addictive than before, which helped make Marlboro, Philip Morris’s flagship brand, the most popular cigarette in the world.
Because of its greater absorption by the body, free base nicotine is also present in smoking cessation products (gums, aerosols, patches, e-cigarettes). In the case of e-cigarettes, however, this use has the disadvantage of making the steam generated very irritating (because of the basic nature of the free base nicotine), which limits the amount that can be absorbed during vaping (see Figure 1). This problem particularly affects heavy smokers who are looking for high doses of nicotine to meet their needs; the irritation or discomfort caused by a high intake of free base nicotine then becomes a hindrance that prevents the transition from the traditional cigarette to the electronic version.
The Juul electronic cigarette circumvents these limitations by using nicotine salts rather than the molecule in its free base form. At first glance, this may seem like an astonishing strategy given that these salts are known to be less well absorbed by the body than nicotine in its free form. However, during the development of their product, the makers of Juul made a surprising discovery: by using certain organic acids to form nicotine salts (in this case, benzoic acid), they observed that these salts could be vaporized at low temperatures and that nicotine was absorbed at a rate similar to that of free nicotine. In addition, the presence of benzoic acid lowers the pH of the vaping solution and causes less irritation in the throat, which allows the user to aspirate larger amounts of nicotine. As a result, Juul can be considered as the first electronic cigarette that is able to fairly accurately replicate the sensation provided by smoking traditional cigarettes, and could therefore represent an interesting tool to quit smoking.
Juul is a recent addition to the world of e-cigarettes and its effectiveness in quitting smoking as well as its health effects remain to be established. Several studies on e-cigarettes show that vaping generates fewer toxic and carcinogenic compounds than traditional combustible cigarettes and there is no doubt that these devices are much less harmful to health. In this sense, Juul may even be superior to other electronic cigarettes, as its higher concentration of nicotine reduces the amount of liquid consumed and it is heated to a lower temperature, which reduces the production of potentially toxic compounds.
The main concern generated by Juul’s phenomenal sales growth remains its high nicotine content that could be addictive for users, especially among young people. Several recent articles have reported that Juul has a strong presence on high school and college campuses in the United States, indicating that it is frequently used by young people, even minors. This use is facilitated by the design of the device that allows them to easily hide it from the authorities and, in some cases, even to vape at school (which has led some schools to ban USB sticks to stop the use of Juul). The flavours of the cartridges, such as “mango” and “crème brûlée”, are also appealing to a younger audience and studies have shown that those who smoke have often started with the use of flavoured tobacco products. The question of whether Juul can be a stepping stone to traditional smoking remains open, but there is some doubt about this, based on recent evidence that youth smoking rates are steadily declining (the proportion of American teenagers who smoked in the last 30 days decreased from 28.3% in 1996 to 5.9% in 2016).
In any event, it is obvious that we must remain extremely vigilant and prevent these new products from favouring the emergence of a new generation of smokers. Alerted by the steady increase in the number of Juul users, the U.S. FDA has recently asked manufacturers of the product to prove that their marketing does not deliberately target youth and describe their plans to limit the use of this product to adults. In response to these requests, Juul Labs promised to invest $30 million over the next three years in research and development to reduce the use of Juul by young people and restrict the product only to smokers who want a less harmful alternative to traditional cigarettes. The pressure from the FDA has also pushed the company to remove its cartridges containing popular flavours from outlets and to stop promoting its product on social media.
Non-combustible tobacco products such as electronic cigarettes are much less harmful than traditional cigarettes and are therefore an attractive option to reduce the harmful effects of smoking. Yet the use of these products continues to be discouraged by the majority of tobacco control organizations, and a lot of misinformation circulating in the media even goes so far as to suggest that they are as or even more harmful than cigarettes. This “demonization” of the e-cigarette means that I am increasingly meeting smokers who refuse to make the transition to these products by mistakenly believing that they do not represent a less toxic alternative to tobacco. This was recently confirmed by a study showing that in 2015, 40% of Americans perceived the e-cigarette to be as or more harmful than the traditional cigarette, triple the number than in 2012. It is important to correct this false impression, because discouraging smokers from quitting traditional cigarettes by opting for e-cigarettes deprives us of a valuable tool in the fight against smoking.
A tobacco rather than a nicotine problem
The disclosure of the “tobacco papers”, i.e., internal notes and confidential reports from tobacco multinationals, revealed the scandalous efforts of this industry to maximize the dependence potential of one of the most addictive substances in the plant world: nicotine. As such, nicotine is not dangerous because it is not carcinogenic and has no major impact on health at the amounts present in tobacco. Rather, it is nicotine dependence that is catastrophic for the health of smokers, because the burning of tobacco generates several thousand highly toxic products, and the repeated consumption of cigarettes exposes them to dramatic increases in the risk of cardiovascular disease, pulmonary diseases and several types of cancers, particularly lung cancer. As is often said, “People smoke for nicotine but they die from the tar.”
This difference in toxicity between nicotine and cigarette smoke means that products that allow the absorption of nicotine, but without combustion, could greatly reduce the damage caused by tobacco. One of the best-known non-combustible tobacco products is the electronic cigarette (or e-cigarette), a device in which a nicotine solution is heated to about 80ºC using an atomizer, which generates an aerosol that takes the form of a white “vapour” similar in appearance to cigarette smoke. The “vaper” inhales a small amount of nicotine, like a smoker, but scientific research in recent years has clearly shown that this vapour contains only a tiny fraction of the toxic compounds that are generated during the combustion of tobacco. This difference in toxicity is well illustrated by a study showing that saliva and urine samples from regular vapers contained much lower amounts of carcinogenic nitrosamines and toxic volatile compounds such as acrolein, acrylamide and acrylonitrile than those of smokers. This is in line with a recent analysis showing that the carcinogenic potential of aerosols emitted by electronic cigarettes is only 0.4% that of traditional cigarette smoke. Based on all currently available data, the Royal College of Physicians of England estimates that the risk associated with the use of electronic cigarettes is at least 95% lower than that associated with smoking tobacco products, and could even be considerably less.
The use of e-cigarettes is a recent phenomenon and it is not yet possible to quantify precisely how far this product can reduce the incidence of tobacco-related diseases. On the other hand, according to the data accumulated for several years in Scandinavia on the effect of another non-combustible tobacco product, snus, one can be optimistic. This product consists of a tobacco pouch (similar to a tea bag) that is applied in the oral cavity, which allows the absorption of nicotine without the need for combustion. Virtually unknown here, snus is the main form of tobacco used by Swedes (20% of regular users, versus 12% who smoke cigarettes), and this preferential use of non-combustible tobacco is associated with significantly lower mortality caused by cancer and cardiovascular disease than in all European countries (see Figure 1, top). In contrast, Swedish women use very little snus and have tobacco-related mortality rates similar to Europeans in general (Figure 1, bottom). The example of snus therefore illustrates how simply substituting combustible tobacco with a non-combustible form can have an extraordinary impact on the incidence of tobacco-related diseases.
Figure 1. Comparison of tobacco-related death rates between Sweden and the average of other European countries. Adapted from Lind (2014).
Modernizing tobacco control
Unfortunately, the potential of these non-combustible tobacco products remains very little used in tobacco control. With a few exceptions, the traditional approach of anti-smoking organizations to reduce the number of smokers remains to advocate abstinence from all tobacco products, either by quitting smoking spontaneously or by using nicotine substitutes approved by the medical community (patches, gums, pharmacological agents). On the other hand, the electronic cigarette is still not regarded as a valid alternative and its use is even strongly discouraged, in spite of the very large number of scientific data showing that these products are much less dangerous for health than the traditional cigarette.
The main argument against the electronic cigarette (or snus) is that these products could serve as a gateway to traditional cigarettes, especially among young people. This conclusion is based on the results of studies (here, here and here, for example) showing that teenagers who have tried e-cigarettes are more likely to smoke a tobacco cigarette than those who have never been in contact with e-cigarettes. But as several experts have pointed out, this interpretation is very problematic because it does not take into account the fact that a young person who is attracted to tobacco will experiment with several forms available, without this meaning that testing one necessarily leads trying another.
In any case, the most important parameter in terms of public health remains the actual rate of regular smoking among young people, and the data collected is very reassuring. Several studies show a very significant decline in the use of traditional cigarettes among teenagers between 2010 and 2016, despite a dramatic increase in the popularity of e-cigarettes during this period. Studies in the UK, where e-cigarettes are now an integral part of a comprehensive tobacco control strategy, show that the vast majority of young people are just experimenting with e-cigarettes and that very few (less than 3%) become regular users. This proportion is even lower among non-smokers, with only 0.4% of them becoming regular vapers. While we must remain vigilant and closely regulate the sale of e-cigarettes to young people, these data clearly show that very few non-smoking young people will become regular smokers following experimentation with an e-cigarette and therefore this product does not seem to be a gateway to smoking.
In practice, studies show that the vast majority of e-cigarette users, young or adult, already smoke traditional cigarettes. Since this combined use of electronic and traditional cigarettes is associated with an increase in the smoking cessation rate, it therefore seems reasonable to encourage (not discourage) smokers to adopt this product in order to reduce their exposure to the toxic compounds of cigarette smoke. Rather than a gateway to smoking, the electronic cigarette could instead be an “exit door”, a concept supported by some European studies showing that about 6.1 million smokers quit smoking with e-cigarettes and that another 9.2 million have reduced their consumption of combustible tobacco with this product. The same is true for snus, where research has clearly shown that this product does not represent a stepping stone to traditional smoking and that its use has on the contrary contributed to drastically reducing the smoking rate in Scandinavian countries.
It is therefore high time to modernize tobacco control, taking into account the harm reduction that can be provided by new non-combustible tobacco products, especially e-cigarettes. Everyone agrees that eliminating smoking altogether is the ultimate goal of tobacco control, but that does not mean that it is undesirable to reduce the harm caused by smoking in people who cannot quit smoking or who persist in doing so. This concept of “harm reduction” has been used for several years to mitigate the negative impacts of high-risk behaviours (drug use, sexual behaviour, automobile transportation) and there is no reason why this approach cannot be applied to smoking.
In this sense, we should welcome the new anti-smoking policy recently announced by the U.S. Food and Drug Administration (FDA). Breaking with the traditional “hard line” of public health organizations that advocate pure and simple abstinence from all tobacco products, the FDA proposes a more nuanced approach combining two main aspects: 1) to oblige cigarette manufacturers to drastically reduce nicotine levels in tobacco to make it non-addictive; and 2) to prevent this reduction from creating an illicit market, encourage the development of less harmful non-combustible tobacco products (such as e-cigarettes) so that smokers who cannot quit may still reduce their exposure to the toxic compounds found in cigarette smoke. This represents an enormous potential for reducing the harm caused by tobacco and it is hoped that this approach will be seriously considered by the tobacco control agencies.
Every year, 6 million people die from diseases caused by tobacco use and if we avoid being too dogmatic, while closely controlling the sale of these products, the substitution of traditional cigarettes with their electronic version could represent a major turning point in human history by preventing millions of deaths in the 21st century.
An article recently published in the Annals of Internal Medicine confirms that users of nicotine substitutes such as electronic cigarettes are much less exposed to toxic and carcinogenic chemicals than regular smokers. By comparing saliva and urine samples from regular “vapers” and smokers, Dr. Robert West’s team showed that those of vapers contained much smaller amounts of several molecules known to contribute to the damages of smoking, including certain carcinogenic nitrosamines and toxic volatile compounds such as acrolein, acrylamide and acrylonitrile. However, this decrease is not observed in vapers who continue to smoke tobacco occasionally, indicating that the e-cigarette can only truly reduce the exposure to toxic compounds in people who completely stop using combustible tobacco. When this is the case, however, these data clearly show that e-cigarettes are much less toxic than traditional cigarettes and that smokers can significantly reduce their risk of developing smoking-related diseases by adopting this form of nicotine inhalation.
Despite this substantial reduction in harm, several official agencies in Canada and the United States are still fiercely opposed to e-cigarettes because they fear it will “renormalize” smoking and, more importantly, become a gateway to tobacco among young people. I understand these concerns very well: when you’ve been fighting tobacco cigarettes for 50 years, it’s hard to accept anything that seems to resemble it.
On the other hand, one may question the relentlessness of some American researchers to try to demonstrate that the use of the electronic cigarette is really a stepping stone towards tobacco cigarettes. For example, a recent study argues that this is indeed the case, although the authors come to this conclusion based solely on the fact that teenagers who had tried e-cigarettes only once in the past month had also tested a tobacco cigarette during the year. As mentioned by Professor Peter Hajek, who heads the Tobacco Dependence Research Unit at Queen Mary University in London, this result means absolutely nothing, as a young person attracted to tobacco will experiment with several forms available, without it necessarily meaning that testing one leads to trying another.
In fact, there is no data that suggests that the use of e-cigarettes leads to smoking, quite the opposite. The proportion of American teenagers who smoke has been steadily decreasing since the late 1990s: for example the “Monitoring the Future” survey reports that the proportion of teenagers who have smoked in the last 30 days has decreased from 28.3% in 1996 to 5.9% in 2016. In addition, since 2011, when the use of e-cigarettes began to increase rapidly in the United States, the proportion of teenagers who smoke has declined sharply from 11.7% to 5.9%. While it is essential to closely regulate the sale of e-cigarettes to young people, it is high time to admit that “vaping” is not a stepping stone to smoking and can even significantly reduce the catastrophic effects of tobacco on health.