History is littered with examples where introducing a new animal species has resulted in catastrophic consequences for the biosphere of a particular area. Regrettably, the same can be said for the introduction of electronic nicotine delivery systems (ENDS) in an attempt to reduce smoking-related health problems.

Vaping products only came on the American market after their producers’ litigation success in 2010. Before that, the FDA had tried to keep vaping out of the US. This led to a rapid increase in the use of ENDS, particularly in high school students. In 2011, only 1% of students were vaping, whilst nowadays, 10-20 % of students are vaping. This should be compared with the 2% of students smoking today!

How does vaping work?
In electronic nicotine delivery systems, a heating coil vaporizes the fluid that has been put in the device. The fluid often includes a vehicle of propylene glycol and glycerol, as well as nicotine. Flavourings — fruit, menthol, mint, candy, and dessert flavours — are common additives. Tetrahydrocannabinol can, and often is, added to the liquid. The aerosolized vapour, formed by contact of the liquid with the heating coil, is then inhaled.

What are the physical effects of vaping?
Whatever the constituents of the fluids used in e-cigarettes are, there will be individual as well as combined effects.

1. Nicotine binds to nicotinic receptors, which stimulate the sympathetic nervous system. This increases heart rate, contractility, workload and blood pressure, which in turn, over longer periods of time, can lead to cardiac remodelling, heart failure, and an increased tendency to irregularities in the heart rhythm (arrhythmias).
2. Propylene glycol and glycerol have emerging evidence of direct cardiopulmonary effects in some people, including wheezing, dry cough, and throat irritation.
3. The flavourings have various effects. Sweeteners, when aerosolized, generate reactive aldehydes, which are thought to be the main contributors to cigarette-induced cardiovascular disease and COPD. Other flavourings can damage DNA in vascular and lung tissue.
4. Inhaled nickel and chromium released from the heating element have been shown to cause pneumonitis and pulmonary inflammation in rat models. Nickel is believed to be a carcinogen.
5. Both nicotine-containing and non-nicotine-containing products can increase platelet activation, reactivity, and aggregation; vascular stiffness; and reactive oxygen species, as well as decrease brain glucose utilization.

Clinical Signs and Symptoms
People who vape are more likely to develop a chronic cough, higher phlegm production, and irritation of the upper airway. Animal studies have suggested that the aerosol can lead to ciliary dysfunction in the airway, and nasal scrapings of people who vape show suppression of immune and inflammatory response genes. In summary, vaping increases the susceptibility to infection.

Vaping can induce asthma symptoms, both in people who have never suffered from asthma and those who are already known to have a predisposition to obstructive airway disease. Lastly, eosinophilic pneumonitis, hypersensitivity pneumonia, and interstitial lung disease have been reported.

EVALI (e-cigarette– or vaping-associated lung injury)

Furthermore, vaping has been associated with a new clinical entity, e-cigarette– or vaping-associated lung injury (EVALI). According to the CDC, in 2020 there were 2807 hospitalizations and 68 deaths from EVALI. Those patients presented with general symptoms such as fatigue and fever, prominent gastrointestinal symptoms and respiratory distress. Their chest X-rays typically showed diffuse symmetric bilateral ground-glass appearance and half of these cases have required ICU admission. Vaping is no laughing matter!

Are there long-term effects?
Most of the known adverse effects are short-term. Simply, e-cigarettes have not been around long enough to ascertain the long-term impact. Until such data are available, animal models serve as the best available surrogates. These animal models show that vaping increases oxidative stress, inflammation, and DNA damage which suggest that vaping may increase the risk for COPD and lung cancer.

In summary

1. Vaping is not a benign pastime or a good idea.
2. The nicotine in the products makes it addictive.
3. There are demonstrated short-term side effects that range from mild to very severe, including ICU-level admission and death.
4. The likelihood of long-term damage to the lungs, heart, and vascular system is high.