Dr Jonathan Ong, Paediatric ST4 (consultant input from Dr Seb Gray)

What are e-cigarettes and how do they work?

E-cigarettes, or vapes, are battery powered and use a small electric current to heat up liquid mixtures, turning them into a vapour which is inhaled. Vaping, juicing or JUULing (named after the most common vaping device) are all terms used to describe smoking e-cigarettes.

How popular are they?

Since they came onto the market in 2003, the e-cigarettes have grown in popularity. In the UK, it’s estimted that the prevalence of vaping amongst children and young people ranges from 5% (in a survey of 11 to 18 year olds) to 7% (in a survey of 16 to 19 year olds). This pretty similar to the estimated prevalence of smoking (5-7%) in the same age groups.

In a US survey in 2019, a staggering 40% of 17 to 18 year olds had tried e-cigarettes, including 35% within the past year. The corresponding figures for 2017 were 15% and 18% respectively. In the 2018 National Youth Tobacco Survey, 5% of middle school students and 21% of high school students reported using e-cigarettes in the past 30 days.

How are vapes marketed to young people?

Under UK law, you have to be 18 years old to buy vaping products. Despite this, three-quarters of current vapers aged 11 to 17 bought their own vaping products. Adults are not legally allowed to buy vaping products on behalf of someone under 18 (known as proxy purchasing).

There are thousands of commercially available flavours designed to tempt young people into vaping (ever walked into a cloud of candyfloss-smelling vape smoke?!) The most common flavours include fruit (73%), mint (55%), menthol (37%), and desserts or other sweets (36%).  E-cigarettes come in seemingly innocent forms that look like pens, USB memory sticks or keyrings, making them more appealing and accessible to young people. 

In a 2014 study, 88% of young adults said they could remember seeing e-cigarettes advertised through at least one medium, including in shops, on the internet, social media, television and film, newspapers and magazines. Other studies have shown that people who remember seeing e-cigarette adverts are more likely to start vaping. In 2018, the US Food and Drug Administration (FDA) published an action plan in response to concerns that e-cigarettes were so highly marketed and accessible to young people.

What do the supporters say?

E-cigarettes have been marketed (for quite a while now) as a useful tool to help people *stop* smoking. In 2021, even NICE published a draft guideline recommending e-cigarettes as a stop-smoking intervention. While there is some evidence that says e-cigarettes can be helpful, there are other studies which question how effective they can be. In a recent trial, paying people to stop smoking was the only effective strategy!

A larger meta-analysis reported that e-cigarettes were actually associated with lower rates of stopping smoking. There haven’t been any clinical trials so far which show a definite benefit of using e-cigarettes compared with other strategies like nicotine replacement by other routes (gum, patches etc), behavioural support or, yes, paying people to stop.    

What are the arguments against?

In 2018, Public Health England claimed that vaping is ‘at least 95% safer than smoking’ – they have since watered down this statement to ‘the use of e-cigarettes is likely to be substantially less harmful than smoking’ in the draft NICE guidelines. BUT! ‘safer’ and ‘less harmful’ are not the same as ‘safe’ and ‘harmless’.

What’s in them?

Most e-cigarette liquids contain nicotine, which we all know is extremely addictive. Vaping liquids come in different strengths; the most common nicotine strength used by 16 to 19 year olds (ITC Youth survey 2019) who had vaped in the past month was under 20 milligrams per millilitre (mg/mL) (54%). 18% used a strength of 20mg/mL or over, and 6% used 40mg/mL or over, which is around the level seen in tobacco cigarettes.

The regulations around e-cigarette liquids are lax, to say the least. This means thousands of vaping fluids are available on the market, but only a small proportion of their contents have been identified. Some of the known contents include propylene glycol and glycerin, polycyclic aromatic hydrocarbons, nitrosamines, volatile organic chemicals, and heavy metals including lead, nickel, tin, chromium and aluminium. Some of these chemicals change when they are heated, to produce new aerosolised compounds with unknown and potentially harmful toxic effects.

Diacetyl (used as a flavouring compound in vaping liquid), is safe if eaten as a sweetener. However, some factory workers who inhaled diacetyl during food manufacturing have developed airway obstruction secondary to bronchiolitis obliterans. Other (in vitro) studies have shown that vaping fluids can promote bacterial adherence, induce oxidative stress and have a pro-inflammatory effect on human bronchial airway epithelial cells and fetal lung fibroblasts. Another study looking at 13 different flavours of vaping fluid showed a decrease in cell viability with exposure to vaping fluids.

Animal experiments give us even more reasons to be worried about the effects of e-cigarette vapour. When one study exposed rats to cigarette smoke and e-cigarette vapour over a period of 5 weeks, it was found that both types of smoke resulted in emphysema- type changes. In mice, chronic vaping fluid exposure altered lipids in their alveolar macrophages and epithelial cells. When these mice were exposed to flu infection, they then had a delayed immune response, increased lung inflammation and tissue damage.

So, there’s a growing collection of evidence showing that vaping fluids have different, but in no way less harmful, effects to those of tobacco smoke. A specific acute lung condition has been identified recently which is related to vaping, known as e-cigarette or vaping product use associated lung injury (EVALI).

As of February 2020, there have been 2,807 hospitalized EVALI cases and 68 deaths in the USA and a further two deaths recorded in the UK. The pathology is varied and includes hypersensitivity pneumonitis, pulmonary haemorrhage, bronchiolitis-associated interstitial lung disease, and eosinophilic pneumonia.

Here’s a study which looks at 98 EVALI patients with progressive shortness of breath, fatigue, and hypoxemia. The median age of the patients was 21 years, and a quarter of them were under 18. Ninety seven percent of these patients presented with symptoms like shortness of breath, cough, pleuritic chest pain, and occasionally coughing up blood. There were also GI symptoms reported – nausea, vomiting, diarrhoea and abdominal pain in 77%. On chest X-rays, all the patients in the study had bilateral lung infiltrates. A quarter needed to be intubated on the ICU, and two died.

Vitamin E acetate, found in some tetrahydrocannabinol (THC)-containing e-cigarettes has been strongly linked to the EVALI outbreak. It was found in bronchoalveolar lavage fluid samples from 48 of 51 EVALI patients, but not in samples from healthy controls. Although 80% of EVALI cases are associated vaping fluids the user has modified with things like THC oil, 20% are associated with pure, commercially available fluids.

Are e-cigarettes a ‘gateway’ cigarette?

In the ASH-Youth survey, 20% of young people said that they tried vaping first before smoking. A further 29% had tried a vaping product but were yet to try smoking. Vulnerable young people, such as those with mental health issues, are at increased risk for starting to use e-cigarettes, tobacco cigarettes (or both) as teenagers.

What should we do as clinicians?

E-cigarettes are getting more popular amongst children and young people, helped along by some devious marketing tricks, easy availability on the high street and internet and the huge variety of products and flavours designed to attract young people. We need to be thinking about e-cigarettes along the same lines as tobacco smoking, in our history taking and advice we give about healthy behaviours. 

There have been passionate calls from a group of paediatric respiratory doctors in the UK, urging Public Health England to protect the children and young people from the harms of vaping, or else risk a potentially devastating epidemic of lung disease. They advocate for tobacco regulations to be extended to e-cigarettes (with strict rules on advertising, packaging and taxation). Up until now, public health messages have been mixed – on the one hand e-cigarettes are promoted as a stop-smoking solution, while there has been little done to communicate how potentially dangerous they could be. 

We don’t yet know the long-term health effects of vaping – but unless action is taken now, we run the risk of repeating the mistakes of history: it took decades to prove the risks of tobacco smoking and introduce effective public health interventions, and we are still paying for the consequences today.