In the March/April edition of the British Journal of Family Medicine, we feature a Burning Questions article on e-cigarettes and smoking cessation, written by Emily James at ASH. And, to support No Smoking Day, we thought we'd give you a sneak peek...

Q. What’s Public Health England’s view on the safety of electronic cigarettes?

A. 2014 review of the evidence commissioned by Public Health England found that the hazard associated with electronic cigarette products currently on the market “is likely to be extremely low, and certainly much lower than smoking”.

An Evidence Update commissioned by Public Health England in 2015 also reported that the amount of nicotine released into the ambient air poses no identifiable risk to bystanders. It stated that: “While vaping may not be 100% safe, most of the chemicals causing smoking-related disease are absent and the chemicals which are present pose limited danger.”

In 2015, the Lancet published an editorial criticising the PHE review. The criticism acknowledged that “tobacco is the largest single cause of preventable deaths in England” and suggested “e-cigarettes may have a part to play to curb tobacco use”. It did not dispute the fact that electronic cigarettes are less harmful then tobacco smoking, but rather the specific estimate at how much less harmful.

Q. Is much known about the chemicals used in electronic cigarettes, and their long-term safety?

A. Although not risk free, the levels of toxicants present in electronic cigarettes are much lower than those present in tobacco cigarettes. In fact, the 2015 PHE review states that: “The constituents of cigarette smoke that harm health, including carcinogens, are either absent in e-cigarette vapour or, if present, are mostly at levels significantly below 5% of doses from smoking (mostly below 1%) and far below safety limits for occupational exposure.”

While it is the nicotine that makes tobacco cigarettes addictive, it is not the harmful component of tobacco smoke. Indeed, Nicotine Replacement Therapy (NRT) is widely used to help people stop smoking and is a safe form of treatment, including during pregnancy and when used long term.

Vapour from electronic cigarettes is usually formed of propylene glycol or glycerol and flavourings. The US Food and Drug Administration has classified propylene glycol as an additive that is “generally recognized as safe” and it is widely used in food and cosmetics. Although mild adverse effects such as throat irritation have been documented, studies that have subjected animals to propylene glycol have also shown no adverse effects.

The other main component of e-liquids is flavourings. While the majority of flavourings are considered safe for oral ingestion, the risks arising from inhalation are largely unknown.

There are some flavourings where an element of risk is known and these flavours should be avoided. This includes some butterscotch or popcorn flavour which use diacetyl. Diacetyl has been associated with irreversible bronchiolitis known as “popcorn lung” in workers at a microwave popcorn plant. However, this is not a commonly used chemical in e-liquids and where it is found it is at lower levels than in conventional tobacco smoke.

For more information see the NCSCT briefing on electronic cigarettes.

[First published March 2016]