Asking for Evidence: are e-cigarettes dangerous?

It is abundantly clear that smoking tobacco cigarettes is bad for your health.  Smoking has been demonstrated by decades of research to be dangerous to you, and those around you.  Tobacco cigarettes contain nicotine, a very addictive substance, alongside a whole host of carcinogens in the tobacco and the cigarette’s filter and papers.  The last decade has seen many governments enact smoking bans in public places, and there is growing evidence that banning smoking has a variety of positive health effects.

The recent wave of e-cigarettes (or electronic cigarettes/vapourisers) has shaken up this pattern of policy.  These e-cigarettes contain an ampoule of liquid nicotine, which is heated to form a vapour, but does not combust like a normal cigarette.  As a result, these e-cigarettes don’t emit toxic chemicals in the same way that tobacco cigarettes do.  However, this breakthrough product is not without controversy.  Battle lines are being drawn between those who are pro “vaping” and those against it.   The USA and the UK are looking to prohibit the sale of e-cigarettes to minors, and some cities are considering banning vaping in public places.

So what are the facts?  Let’s play a game of True or False.

True or False: e-cigarettes help you quit smoking

It has been suggested that e-cigarettes may help those trying to quit smoking, as they are distant cousins of nicotine inhalers that are used as part of nicotine replacement therapy (NRT) to help control cravings.  The World Health Organisation says:

The efficacy of [e-cigarettes] for helping people to quit smoking has not been scientifically demonstrated.

This 2011 review of studies, investigating whether e-cigarettes could be used to help smokers quit, highlights a mixed bag of results.  E-cigarettes can deliver nicotine more rapidly than a medical nicotine inhaler (although less so than a tobacco cigarette).  However, the amount of nicotine delivered by a smoking cessation tool only weakly reflects its ability to suppress cravings.  In fact, some studies showed that reducing the nicotine levels in the cigarette actually improved its ability to suppress cravings.  The latest report from Smoking in England suggests that smokers are using e-cigarettes instead of NRT as a way to quit, and that e-cigarettes are predominantly used by smokers rather than non-smokers, but the statistical evidence is still weak.

Verdict: Possibly True.  Having some sort of cessation aid often has a positive influence on quitting smoking, but there isn’t a strong consensus that e-cigarettes are better than their NRT competitors, which are licensed and available on the NHS.  We need more evidence!

True or False: e-cigarettes contain less toxins than tobacco cigarettes

This study from last year looks at the levels of toxins and carcinogens in several different brands of e-cigarette, by sampling the vapour they produce and separating the various compounds that make up the vapour, using chromatography and spectroscopy.   They found that some of the toxins in tobacco cigarettes are also present in e-cigarettes (such as formaldehyde), but the levels of these toxins was significantly lower (between 9 and 450 times lower!). Carcinogenic compounds were also detected, but these were present at the same level as in nicotine inhalers and gum.

Verdict: True.  E-cigarettes aren’t 100% clean, but they are much cleaner than conventional cigarettes.  However, the fact that we’re relying on independent verification of an e-cigarette’s ingredients rather than reading them off the pack is concerning.  This is another reason why strong regulation is needed, so that consumers can make informed choices.  Also, there are studies that show nicotine consumption increases the activity of genes associated with some cancers. The NHS does not believe that this effect is sufficient to encourage patients to stop NRT, but it’s not clear how vaping will come into this.

True or False: e-cigarettes don’t burn, so in this respect are less dangerous than cigarettes

There have been several recent news stories of e-cigarettes catching fire while charging, or apparently catching fire while in use in high oxygen environments such as hospitals.

Verdict: Certainly not true, but this is anecdotal evidence at best.  A lack of regulation might be responsible for unsafe products entering the market, but we need more evidence!

True or False: Vaping is safer for those around you than smoking.

This study looked at whether “passive vaping” is a phenomenon in the same way that passive smoking is.  A volunteer smoker sat in a test chamber and used an e-cigarette, and the air in the test chamber was sampled.  They found that e-cigarettes produced around ten times less fine particles (aerosols) than conventional cigarettes, and that the level of formaldehyde in the air was extremely low.

Verdict: True, vaping is relatively safer for those around you than smoking.  But, vaping does still produce quite a bit of aerosols, and the authors noted that in an environment simulating the lung, the average size of the aerosols decreases.  So far, we don’t have enough data to quantify the effect of vaping on the human throat and lungs (although there is some evidence that those who vape experience throat irritation thanks to propylene glycol).

The Bottom Line

So far, the evidence suggests (weakly) that vaping is relatively safer than smoking – relatively being the operative word.  Smoking’s pernicious effects were discovered through studies that operated over long time periods, usually referred to as longitudinal studies.  Vaping hasn’t been around long enough for longitudinal studies, which is why organisations like the World Health Organisation remain unconvinced about its benefits.  So scientists can’t say with certainty whether e-cigarettes are harmful or not.  So if you hear someone declaring that e-cigarettes are good or bad with great certainty, be sure to take their words with a pinch of salt.