January, 2016:

If your New Year’s resolution was to stop smoking, and you were looking for support to help you quit, then recent headlines suggesting e-cigarettes ‘aren’t any safer than tobacco’ might have raised an eyebrow or two.

Since Christmas, we’ve seen three sets of critical headlines about e-cigarettes, each looking at a different aspect of a device now used by millions across the UK.

But how accurately do these stories reflect the scientific evidence? What do we really know about how safe e-cigarettes are? Can they really help you quit? And do candy flavours attract kids?

If you were to go on the media reports alone, you’d be forgiven for being alarmed.

But as is so often the case in the reporting of science and risk, taking a deeper look behind the headlines reveals a very different story.

Just because they’re not “safe” doesn’t mean they aren’t “safer”

The first study to make the headlines suggested that e-cigarettes were ‘as harmful as tobacco’.

After studying cells in the lab, the researchers found some indications of increased levels of DNA damage and cell death in those treated with e-cigarette vapour.

This led one of the researchers to tell the media, “I believe [e-cigarettes] are no better than smoking regular cigarettes.” (More on this statement below).

The most important thing to remember here is that this was a study looking at the effect of chemicals on cells in a lab. Although this can be useful, it obviously can’t give a clear idea of what the impact would actually be in your body. So any claims of impact on health based only on lab studies will always be far-fetched.

The study also looked at an extremely high concentration of vapour. As the researchers admitted at the time, “it was similar to someone smoking continuously for hours on end, so it’s a higher amount than would normally be delivered.”

It boils down to this: the study showed that it might be worse for your cells to be exposed to e-cigarette vapour than the air in a lab. So e-cigarettes might not be 100 per cent harm free. And previous studies have shown there may be some dangerous chemicals present in vapour – so this isn’t a surprise. And there’s little in life that really is ‘safe’ – even drinking too much water can kill you.

But here’s the big caveat. The researchers also treated some cells with tobacco smoke. These died within 24 hours. Those treated with e-cigarette vapour were still alive to experiment on 8 weeks later.

So, contrary to the headlines, this study actually suggests that using e-cigarettes may be far less dangerous than smoking.

You’d never believe that from the headlines though.

There were a few great critiques published shortly afterwards, (notably this one in the Guardian) and the press release was amended (more than a week later) to include the following correction:

“ Contrary to what was stated or implied in much of the news coverage resulting from this news release, the lab experiments did not find that e-cigarette vapor was as harmful to cells as cigarette smoke. In fact, one phase of the experiments, not addressed in the news release, found that cigarette smoke did in fact kill cells at a much faster rate. However, because similar cell-damage mechanisms were observed as the result of both e-vapor and regular cigarette smoke, Dr. Wang-Rodriguez asserts, based on the evidence from the study, that e-cigarettes are not necessarily a healthier alternative to smoking regular cigarettes. As stated in the journal paper and the news release, further research is needed to better understand the actual long-term health effects of ecigarettes in humans. ”

But we’re concerned that, as far as public perception goes, the damage may already have been done.

How can you tell if something helps people quit?

So the scientific evidence on e-cigarette vapour to date suggests it’s far safer than tobacco smoke.

But can e-cigarettes actually help you quit?

Here we come across the second set of unfortunate stories, after a systematic evidence review and meta-analysis published last week claimed that those using e-cigarettes seemed to be less likely to quit smoking than those not using the devices.

But, again, there are a number of serious problems with the review.

Systematic reviews and meta-analyses are usually extremely useful, because they pull together all the evidence in one area, to paint a fuller picture than one study alone.

However the relationship between this picture and reality depends entirely on the quality and relevance of the original studies that are included. In this case, since there haven’t been many high-quality trials exploring whether e-cigarettes help people quit smoking, the researchers included a range of different types of studies.

The gold standard of evidence is the randomised control trial, which, in this case, would compare a group of smokers trying to quit using a nicotine-containing e-cigarette, to a similar group using nothing (or an e-cigarette without nicotine). But here’s the problem – there have only been two published studies like that.

A 2014 meta-analysis of these found people using nicotine via an e-cigarette were more likely to successfully quit than those using e-cigarettes without nicotine.

Last week’s review included both of these randomised trials alongside a range of other ‘realworld’ non-trial studies of e-cigarette use. This is a big problem. Whatever their strengths individually, these studies didn’t use consistent measurements – neither of e-cigarette use, nor of whether people had actually quit – so the studies aren’t necessarily comparable. And so including them together in a meta-analysis is questionable, at best.

Even so, when the analysis only included studies where people were actively trying to quit (as opposed to using e-cigarettes for other reasons) the results became inconclusive – people who said they’d ‘ever’ used an e-cigarette weren’t any more or less likely to succeed.

Furthermore, some of the studies included only looked at current smokers and asked about ecigarette use. This would exclude anyone who had used an e-cigarette but successfully stopped smoking.

Quitting smoking can be incredibly hard. Someone trying an e-cigarette once probably wouldn’t have any better chance than if they hadn’t. Whatever support aid is used it would need to be as part of a concerted quit attempt and used enough to deliver sufficient nicotine to wean yourself off tobacco, and preferably alongside specialist support from a Stop Smoking Service to get the best possible chance of quitting.

E-cigarettes aren’t a magic bullet, but that doesn’t mean they couldn’t be a useful weapon in our arsenal against tobacco. The evidence for quitters using these products both within the Stop Smoking Services and without points towards this being the case in the UK.

The impact of advertising and flavours on kids

Whether or not they’re ‘safe’, or help people quit, another big concern about e-cigarettes is that they could encourage children to start smoking – either by exposing them to nicotine (the ‘gateway’ argument) or by making smoking seem more normal again (the ‘renormalisation’ argument).

The first of these arguments isn’t supported by the evidence to date: surveys across the UK last year found that young people who hadn’t smoked weren’t using e-cigarettes.

But a small study published this week found young people rated printed adverts with flavoured e-cigarettes more appealing than those without flavours, leading to headlines suggesting children are being lured in with sweet flavours.

But when you dig into the detail, again it’s a more complex picture – the young people in this study, including those who saw the flavoured e-cigarette adverts, had negative views about ecigarettes, and said they didn’t intend to buy them. And, perhaps more importantly, it didn’t find any evidence that e-cigarette adverts increase the appeal of regular cigarettes.

There are now measures in place to protect young people (e-cigarettes cannot be sold to under 18s, and further legislation heavily restricting advertising will come into force in May) but it’s still important to continue looking at how e-cigarette adverts might appeal to children, and to track use of both e-cigarettes and tobacco cigarettes to make sure there isn’t a negative impact from these products.

However, Linda Bauld, Professor of Health Policy at the University of Stirling (and our Cancer Prevention Champion), said the study “should provide some reassurance to those who say that e-cigarette advertising will result in a new generation of tobacco smokers.”

Where does this leave us?

When you look at the bigger picture, rather than the headlines, the evidence so far actually points towards a positive role for e-cigarettes in helping combat the biggest preventable cause of cancer. However none of the questions posed here – on safety, effectiveness and impact on children – have full answers.

As we’ve said before we need years of good quality science before we can definitively answer these questions, and at Cancer Research UK we are working towards that. But for now the evidence we have suggests e-cigarettes are far safer than smoking tobacco, they might help you quit and non-smoking children aren’t being lured into using them regularly.

While the evidence on e-cigarettes continues to accumulate, and the media controversy rages on, if you’re looking for evidence-based inspiration to quit smoking in 2016, speak to your GP or local Stop Smoking Service, or check out our website… but maybe keep reading the headlines with an appropriate dose of scepticism.

Nikki Smith is a senior health information officer at Cancer Research UK