Vaping during childhood poses greater health risks than previously thought

Electronic cigarettes, or vapes, were introduced in the 2000s to help people quit smoking, a dangerous habit that kills half of users for life.¹. Supported by numerous public health messages according to which vaping is 95% safer (see go.nature.com/4ixya3r) than cigarettes, manufacturers and some doctors have been keen to extol the virtues of these electronic systems for delivering nicotine to confirmed smokers who are dependent on this substance.

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Yet the safety of e-cigarettes is not well established – even the evidence behind the 95% claim is difficult to pin down. Health problems associated with e-cigarettes began to emerge a decade ago. As the use of vapes becomes more widespread, the evidence has become irrefutable. Some of the side effects are extremely concerning.

In particular, it has become clear that these products represent an attractive gateway to nicotine addiction for non-cigarette smokers, including children.

A systematic review published in August (of which we are co-authors) identified a range of health consequences for children and young people who vape.². The magnitude of likely harm is broader than expected and increasingly evident in the children we see in hospital practice.

Here we outline the risks and call on governments to act to legislate where necessary and ensure these laws are effectively enforced.

Medical tools

By design, e-cigarettes are very effective in delivering nicotine, at levels comparable to or higher than traditional tobacco cigarettes.³. Their effectiveness probably explains their effectiveness as an aid to quitting smoking in certain smokers. A meta-analysis showed that they are more effective than other nicotine replacement therapies for smoking cessation.⁴. But they are not without risk.

Nicotine is a highly addictive substance known, based on decades of studies on smokers, to harm fetal and adolescent brain development.^5,6. Even intermittent, low-dose use can quickly lead to symptoms of nicotine dependence.⁷. These effects are particularly pronounced during adolescence, with some young users reporting symptoms of addiction, including cravings and withdrawal from casual exposure.⁸.

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E-cigarettes have been shown to contain harmful substances, including heavy metals, such as lead; toxic carbonyls; nanoparticles; and unregulated substances, such as synthetic cannabinoids⁹. Long-term health problems have not yet emerged, but these substances are known to be pro-inflammatory, immunosuppressive, carcinogenic and highly addictive.

The continued increase in vape consumption since their development has coincided with the rediscovery of nicotine salts. In the 1970s, manufacturers perfected their processing techniques to remove protons and organic acids from natural nicotine salts. The resulting unbound (free base) nicotine is discharged and attracted to fat. These chemical properties result in faster absorption and transit to the brain, as well as a more intense sensory experience or nicotine “hit.”¹⁰. Free cigarettes quickly dominated the market.

In 2017, vape manufacturers discovered that salt-based nicotine tasted milder and sweeter. They added these salts to vapes to enhance the sensory experience. The effect is particularly strong in people who have never smoked and are not used to inhaling freebase nicotine.¹¹.

Studies have shown that certain nicotine salt products can produce higher and faster peaks in blood nicotine levels.¹². Vape manufacturers also quickly seized the opportunity to make these products attractive to young users with sweet and fruity flavors and colorful packaging.

Health Risks of Vaping in Children

Early studies on the possible risks of vaping for all age groups focused on acute effects, such as an immediate reduction in lung function or the appearance of respiratory symptoms.¹³. But this is likely just the tip of the iceberg when it comes to overall damage. In our systematic review, we identified a worrying range of possible risks associated with vaping at a young age.

As respiratory pediatricians, we were not particularly surprised to find that childhood vaping was consistently associated with coughing, chest discomfort, wheezing, and wet coughs. The direct effects of inhaling hot gases and chemicals could also explain the observed increase in oral diseases, such as gum inflammation, ulcers, and dry mouth, as well as eye symptoms such as itching, redness, dryness, blurriness, and pain in the studies we reviewed. An increase in allergic conditions such as atopic dermatitis and allergic rhinitis has also been reported.

We expected that nicotine, a powerful central nervous system stimulant, would have effects beyond the respiratory system. Yet we were surprised to see how youth vaping is associated with poorer mental health. Depression, panic disorder, anhedonia, and suicidal ideation were all more commonly reported among people who vaped. The fact that young e-cigarette users are almost twice as likely as non-users to have suicidal thoughts or plans, or suicide attempts, is concerning.

There was also concern that it could have harmful effects on unborn babies. Our review found higher rates of premature births, low birth weight for gestational age, abnormal reflexes and motor immaturity in infants born to mothers who vaped.

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The most alarming finding for us was the strong evidence that vaping among children and youth who have never smoked predicts and increases the likelihood of later smoking conventional cigarettes. E-cigarette users were generally 2 to 12 times more likely than non-users to subsequently start smoking.

This return to a deadly practice is particularly galling given the healthier choices that children born after the millennium were beginning to make. Dramatic declines in alcohol use, drug use, teenage pregnancy, crime and smoking among people aged 16 to 24 in the UK led to them being dubbed the Sensible Generation by the media in 2018.

Although vaping is a useful addition to smoking cessation programs for adults, its baseless and simplistic promotion as a safe alternative to smoking cigarettes has led to unintended consequences for non-smoking children and youth.

The increase in vaping among children and young people is a global phenomenon that spans very different continents and cultures.¹⁴. The duration of vaping varies depending on the country.