The absence of long-term risk assessments does not justify stifling the development of new, potentially less harmful nicotine products.

By Clive Bates

It’s a common refrain: “We just don’t know the long-term risks of vaping.” Those who oppose the transition of the consumer nicotine market from combustible to noncombustible products will often argue, correctly, that there are no long-term studies of the safety and health impacts of vaping or heated-tobacco products. What is wrong is to assume this is a slam-dunk clincher and that the argument should end there. Let us examine this claim in more detail.

First, it is a statement of the obvious. We have not yet invented time travel and cannot venture forward to 2050 to find out what happened to life-long vapers. There will be no long-term studies until the long term has elapsed and the studies have been done. We have had about 10 years of science on vaping, and the story is positive so far, but we will not have 40 years of studies until 2050.

Second, at least for now, almost everyone who vapes or switches to a heated-tobacco product is currently or has recently been a smoker. For that reason, long-term data on vaping will be “contaminated” with health consequences of prior smoking, and this will be difficult to untangle. It will be possible to follow cohorts of those who never smoked prior to vaping, but at present, these are a small fraction of the total user population. I hope that share will grow (there should be no need to go to a safer form of nicotine via the most dangerous) but that is not something the authorities wish to encourage.

Third, some activists argue that it took years for us to discover the health risks of smoking. Smoking took off in the early 20th century, but it was not until the 1960s that the U.K. Royal College of Physicians and the U.S. Surgeon General issued their blockbuster reports on smoking and health. Surely, we should expect discoveries to emerge over decades. But this perspective ignores the march of scientific progress over the past 60 years. Today’s field of systems toxicology would be unrecognizable to the boffins of the 1950s. If cigarettes were invented today, a modern lab would need about half a day to establish the extraordinarily high risk, and that includes writing up the paper. We would not need to wait 40 years to declare that a hypothetical newly introduced cigarette would be very harmful to health.

Fourth, it is true that we do not have long-term epidemiology for vaping, but that does not mean we know nothing. There is a lot of data that helps us assess what long-term risks are likely to be. These come from chemical analysis of the vapor aerosol and measurements of toxins in the blood, saliva and urine of users of the products. We are also seeing more measurements of improving indicators of health in users who have switched from smoking to smoke-free products. The totality of what we do know is impressive, and it all points toward much lower risks over the long term.

Fifth, some analysts advocate a “precautionary approach” to address long-term but uncertain risks. This would mean some mix of prohibition, taxation, regulation and off-putting communications to deter use until someone can prove that the products are safe—or safe enough. The precautionary principle is perhaps the most shamelessly abused concept in all of policy-making (though it is a crowded field). The precautionary principle is not a free pass to ban anything with uncertain risks. It is really a sophisticated form of risk assessment that requires taking account of the consequence of both action and inaction and the consequences of being wrong. Given that smoke-free products are alternatives to smoked products, and we know beyond doubt that these are harmful, then there is every possibility that obstructing access to what looks like a much safer product will do more harm than good. In what I regard as the most important passage in its 2016 report, Nicotine without smoke: tobacco harm reduction, the Royal College of Physicians captured this challenge:

“A risk-averse, precautionary approach to e-cigarette regulation can be proposed as a means of minimizing the risk of avoidable harm, e.g., exposure to toxins in e-cigarette vapor, renormalization, gateway progression to smoking, or other real or potential risks.

However, if this approach also makes e-cigarettes less easily accessible, less palatable or acceptable, more expensive, less consumer-friendly or pharmacologically less effective, or inhibits innovation and development of new and improved products, then it causes harm by perpetuating smoking. Getting this balance right is difficult.”

Generally, the precautionary principle is most applicable where the risks are novel, systemic, irreversible and cause uncontrollable destabilization—for example, introducing new species or pathogens into an ecosystem or increasing the heat in the atmosphere. Vaping risks are not like this.

Sixth, it is often assumed that “no long-term studies” implies there are bound to be risks but we just haven’t found them yet. However, it may turn out that the risks are negligible or well within the range of voluntarily accepted risks associated with living a normal enjoyable life. It is even possible that there may be health-protective effects that go beyond ameliorating the risks of smoking. It is possible, for example, that nicotine may have protective effects against some forms of neurodegenerative disease.

Seventh, it is possible that unexpected risks will emerge. But it is likely that many plausible risks can be dealt with through regulation. For example, a recent study by Farsalinos and Lagoumintzis investigated the toxicity of flavor compounds used in e-liquids. It found that “one chemical (methyl cyclopentenolone) was found at a maximum concentration 150.7 percent higher than that needed to be classified as toxic.” There is an obvious regulatory response: Stop the use of this compound or ensure it is used only in concentrations well below the toxic threshold. This response is possible with vapor products because the vapor aerosol is more or less a heated version of the e-liquid, so controlling ingredients and contaminants in the e-liquid will also control human exposure. The same is not true for cigarette smoke. Vapor products generally operate below 300 degrees Celsius, but the temperature in the burning tip of a cigarette can exceed 900 degrees Celsius. At these higher temperatures, there is much more energy to break chemical bonds and to create thousands of new “products of combustion,” which can react with each other to create still more compounds. The combustion process of cigarettes is far more complex and chaotic than the heating process of vapor products and leaves the cigarette designer with only limited options to control toxic exposures. This is one reason why industry engineers have struggled to make a “safer cigarette.”

Eighth, a common variant on the “we just don’t know” argument is that public health was badly caught out with “light and mild” low-tar cigarettes. These appeared to be safer and even had some public health endorsements as a harm reduction approach. These products appeared to be safer only when smoked by machines with fixed smoking regimes. It turned out that real humans adjusted their smoking behavior by blocking filter ventilation holes or drawing more frequently and deeply on the cigarette. Smokers adjusted their behavior—a process known as compensation—to achieve their desired dose of nicotine. And with the nicotine, they got the exposure to toxins in the smoke and were no better off. The situation with smoke-free products is very different. Low-tar cigarettes mostly just diluted smoke with air—the ratio of toxins to nicotine barely changed. Vapor products work by dramatically reducing the ratio of toxins to nicotine in the aerosol. So for a given dose of nicotine, a vaper will receive a much lower exposure to toxins than a smoker. The “light and mild” argument is misusing an analogy that does not hold true in reality. We should not use a mistake in the understanding of light cigarettes to justify a mistake in the understanding of smoke-free products.

My concern is that the argument about the lack of long-term studies is essentially tactical: a rhetorical gambit designed to create an insurmountable evidence hurdle that will apply indefinitely. I do not believe it is a sincere attempt to grapple with inevitable uncertainties and to make the best decisions possible with the available evidence. To test the sincerity of those making this argument, I have devised what I call “the snus test.” Snus is a form of oral tobacco popular in Scandinavia. So my question is: Do you accept that the long-term evidence for snus use in Scandinavia shows it has reduced smoking prevalence and the burden of disease? If the answer is “no” and some other justification is offered, it is clear you are not dealing with a sincere truth seeker.

The theme of this year’s Global Tobacco and Nicotine Forum (GTNF) is “More choice, less risk.” The GTNF will be held Sept. 24–26, 2019, in Washington, D.C. See www.gtnf.org for more information.