How Much Evidence Is Enough to Exonerate E-Cigarettes?
E-cigarettes have a PR problem. From concern about young people illegally obtaining and using them to being wrongly implicated in the outbreak of EVALI (i.e., e-cigarette or vaping product use-associated lung injuries), e-cigarettes get a lot of bad press.
This has translated to misperceptions about their risk relative to combustible cigarettes. Between 2012 and 2018, the percentage of adults who incorrectly perceived e-cigarettes as being more harmful than combustible cigarettes substantially increased from as low as 1.3 percent to 8 percent. Additionally, by 2018, 43 percent incorrectly perceived the two products as equally harmful, up from about 36 percent. It’s not hard to see how people are arriving at these misperceptions when you consider the discourse being produced by health authorities.
Medical Advocacy Organizations Remain Skeptical of Tobacco Harm Reduction
Recently, we conducted a discourse analysis of position and policy statements produced by medical advocacy organizations. Although the statements were supported by evidence, they rarely provided a complete discussion of how e-cigarettes fit into the tobacco control environment. Some of the statements acknowledged that e-cigarettes are less harmful than combustible cigarettes, but the statements still focused disproportionately on the potential harms of e-cigarettes and downplayed, or completely dismissed, them as a harm reduction tool. Many of the statements discussed a need for additional research to establish e-cigarettes’ effects on health and as cessation devices. These two things likely contribute to the perception that there is insufficient evidence to establish e-cigarettes as being less harmful than combustible cigarettes.
When medical advocacy organizations suggest that there is not enough evidence to support e-cigarettes’ reduced-risk profile and cessation utility, they are presumably commenting on the absence of long-term, longitudinal epidemiologic studies documenting a positive safety profile of e-cigarettes and large clinical trials showing e-cigarettes to be effective cessation aids. The medical advocacy organizations are correct that we need to continue researching these topics; however, when research is published that supports e-cigarettes as tools for combustible cigarette cessation, it is often overlooked. In fact, a large body of global evidence supports e-cigarettes’ relative safety and potential as cessation aids.
Existing Evidence of E-Cigarettes’ Favorable Relative Risk Profile and Cessation Potential
Without understanding the health impacts of nicotine, it is difficult to accept e-cigarettes as a harm reduction tool. Nicotine is the addictive element of tobacco products. It is not, however, recognized as a key contributor to the health conditions generally associated with tobacco use. To be certain, nicotine is not entirely without health effects, but the extent to which these observable effects lead to the manifestation of disease is still a topic of debate.
The e-liquid used in e-cigarettes generally contains other ingredients besides nicotine, like humectants and flavorings. When heated, e-liquid produces far fewer chemicals than combustible cigarette smoke. In the body, this translates to lower levels of biomarkers of potential harm among exclusive e-cigarette users compared to people who smoke. These points are why e-cigarettes are generally regarded as being less harmful than combustible cigarettes. Furthermore, e-cigarettes have been on the market in the United States since 2007, and research has yet to deliver evidence of a causal link between nicotine-containing e-cigarette use and disease development or progression.
It is true that the Food and Drug Administration (FDA) has not approved any e-cigarette as a cessation device. It should also be noted that no e-cigarette product has been submitted to the FDA for this designation, although there is no guarantee that an e-cigarette would pass muster if one did pursue this pathway. Nevertheless, several systematic reviews assessing the available evidence on e-cigarettes as cessation aids have found positive results. Reviews by the National Academies of Sciences, Engineering, and Medicine and the Australian Department of Health have found some limited evidence that e-cigarettes can help people stop smoking. Furthermore, a 2022 Cochrane review concluded with high certainty that the use of nicotine-containing e-cigarettes increased the rate of successfully quitting smoking compared to traditional nicotine replacement therapy.
Finally, the U.K. is about to put e-cigarettes’ cessation potential to the test. The country is distributing one million vaping starter kits to people who smoke and is providing behavioral support to help them switch from combustible cigarettes to vaping. The “Swap to Stop” program hopes to improve health and decrease the national smoking rate.
The Precautionary Principle and Dealing with Remaining Questions
Without a doubt, science still has questions to answer about e-cigarettes, and questions will always remain. However, for any problem, eventually a tipping point is reached where the preponderance of the evidence points to a conclusion. This relates to the precautionary principle, which asserts that, in the presence of scientific uncertainty regarding a threat to health, precautionary actions should be taken until safety can be assured. Health organizations often operate on this principle when making suggestions.
The questions then become, what evidence is sufficient to convince health organizations of e-cigarettes’ harm reduction potential, how does science produce evidence that confirms or rejects this potential, and how long are we willing to operate under the status quo while waiting for conclusive evidence?
The first question we can answer only with speculations. Perhaps long-term epidemiologic studies are needed. Or maybe FDA approval of an e-cigarette as a cessation product or authorization of a modified risk marking claim would be enough. More clinical trials may also be necessary.
The second question seems more straightforward but is also complex. No study is perfect, and establishing causation (or lack thereof) is quite challenging. Agreeing on a set of methods or best practices for studying e-cigarettes and vaping may be one way to help resolve tensions and conflicting study results.
Question three is subjective and encompasses the first two questions. About 480,000 Americans die each year from smoking-related illnesses. And although the majority of people who smoke want to quit, fewer than one in 10 succeed each year. Precaution with new tobacco products is wise; however, existing cessation methods are failing most people trying to quit. We are facing the inevitable crossroads of perfect versus good enough—if appropriately regulated e-cigarettes can help some people now, isn’t that better than helping nobody while waiting indefinitely for research that proves e-cigarettes present little to no health risks, presuming that is the desired finding?
Because science builds on itself, it is likely that time is the only thing that will help definitively determine the relative risk and net public health impact of e-cigarettes. We may also find that these values end up differing by product and population. Yes, questions remain about e-cigarettes; however, leaning into the precautionary principle is getting harder. The absolute risk of combustible cigarettes, and thus their harm to public health, is so high that exercising extreme caution with e-cigarettes may be inadvertently harming people who smoke. To benefit public health, perhaps it is time for organizations to begin specifying what evidence they need to exonerate e-cigarettes. It would be a sad day for science if the answer is that no evidence is convincing enough.
