Australia plans to ban recreational vaping in a move designed to head off what they fear is an industry that will get a new generation of young people addicted to nicotine. Part of the justification for the ban is concern over the health risks of vaping, or e-cigarettes, which use heat to turn a liquid into a vapor which is then inhaled. Often the liquid contains nicotine and may also be flavored, a practice critics argue is targeted at children.
Vaping was initially promoted as a safer alternative to smoking, and a way for smokers to quit their nicotine addiction. But at the same time non-smokers have been taking up vaping. The Australian ban seeks to eliminate this latter path, so-called recreational vaping, while making it easier for smokers to get prescriptions for vaping as a method of quitting. Australia also seeks to regulate the contents of vaping fluid, including nicotine content and flavoring. There is also concern that a ban might simply turn users toward the black market in vaping products.
Regardless of the ultimate regulatory strategy, what is the current evidence on the health effects of vaping? While there is concern that the evidence is still preliminary, there have been enough studies to spawn a number of systematic reviews. A 2021 review – Vaping and lung cancer – A review of current data and recommendations, found:
E-cigarette devices and vaping fluids demonstrably contain a series of both definite and probable oncogens including nicotine derivatives (e.g. nitrosnornicotine, nitrosamine ketone), polycyclic aromatic hydrocarbons, heavy metals (including organometal compounds) and aldehydes/other complex organic compounds. These arise both as constituents of the e-liquid (with many aldehydes and other complex organics used as flavourings) and as a result of pyrolysis/complex organic reactions in the electronic cigarette device (including unequivocal carcinogens such as formaldehyde – formed from pyrolysis of glycerol).
This study is essentially looking at hazard, the presence of known and possible cancer causing agents in vaping fluid. The reason to take this approach is that there is likely a 20 year delay between exposure and diagnosis with cancer, so by the time there is clear evidence for an actual increase in lung cancer we will already have a new generation addicted to vaping nicotine. But still, this kind of data has to be put into perspective – it is a hazard, a potential risk.
Because of this delay in terms of developing cancer, some studies focus on acute or short term lung damage. A 2021 review of these studies, E-Cigarette or Vaping Product-Associated Lung Injury: A Review, finds:
Since March 2019, there has been an ongoing epidemic of acute lung injury secondary to the use of e-cigarettes, with over 2600 cases and 60 deaths reported all over the United States.
A significant proportion of patients hospitalized with e-cigarette- or vaping product-associated lung injury have required admission in the intensive care unit, with mechanical ventilation needed in up to one-third of patients.
This acute injury is treatable, with generally (but not universally) good outcomes, but the concern is that these acute lung injury cases are the tip of the iceberg. They represent cases with symptomatic acute lung injury, which raises the possibility of chronic, asymptomatic, or mildly symptomatic lung injury. Again, this type of injury may take decades to fully appreciate.
Another 2022 review, Vaping-Associated Lung Injury: A Review, gives this summary:
Adolescents who use e-cigarettes commonly report an increased cough and wheeze, and studies have shown an association with e-cigarette use and asthma exacerbations. However, it is not yet clear if chronic e-cigarette use by itself can cause COPD in a clinical setting or if the substitution of e-cigarettes for combustible tobacco products can prevent or slow the development of COPD. There is also data to support a correlation between e-cigarette use and impaired host defence. It appears viral responses are compromised, and bacterial clearance by macrophages and neutrophils appears to be reduced. This allows increased adhesion and colonisation of bacteria and possibly an impaired infection-fighting ability.
A 2020 review, A review of toxic effects of electronic cigarettes/vaping in adolescents and young adults, also includes extrapulmonary effects.
Additionally, there have been more recent studies showing extrapulmonary effects including cardiovascular, immunologic and neuro-developmental effects. Many of these effects are likely dose-dependent.
A 2021 review of studies looking at periodontal effects found:
This study concluded that there is not enough evidence to fully characterize the impacts of vaping on periodontitis. However, within the limitations of our review and the selected included studies, the available results point to increased destruction of the periodontium leading to the development of the disease.
If we take a risk-vs-benefit approach to vaping, we can review the evidence of whether or not it works as a smoking-cessation tool. From the 2022 review above:
E-cigarette use has grown exponentially, particularly amongst adolescents. While they were originally marketed as a smoking cessation tool, evidence for a role in smoking cessation has been inconclusive. There is some evidence that nicotine-containing products may have a role in risk reduction for active smokers but, conversely, may encourage the initiation of cigarette smoking in non-smokers.
The evidence for benefit is mixed and unclear. Using vaping as a nicotine delivery alternative does seem to help some smokers quit, but the number is low (18% in one study) with a high relapse rate, perhaps higher than other methods of quitting. Meanwhile vaping leads some non-smoker to take up tobacco use, and some smokers become dual-users, with demonstrated increased toxicity. Therefore, just in terms of smoking cessation, it is unclear if there is a net benefit to vaping, which likely means that there is no large benefit.
Meanwhile, vaping is leading to a dramatic increase in younger people taking up vaping directly. There is clear evidence at that point of toxicity, exposure to hazardous materials, acute lung injury, periodontal injury, and some extrapulmonary effects. It is still unclear what the long term risks are, because there simply hasn’t been enough time to see these effects and gather that data. Also, as with smoking, we can’t ethically do a randomized controlled trial, so we must infer the risks from toxicity and epidemiological data.
The evidence clearly shows that we should not be complacent about the risks of vaping. There is legitimate cause for concern about a product that is addictive, may lead to more harmful behavior (smoking), and targeted toward children with sweet flavoring and attractive packaging, a practice that the evidence shows is clearly working. Whether or not Australia’s ban is effective or the best approach, time will tell. But the justification is reasonable.