E-cigarettes are revolutionising the fight against smoking addiction. Emily James from ASH looks at their safety and efficacy, as well as how they compare to other cessation methods
Q What are electronic cigarettes?
A Electronic cigarettes, (also known as e-cigs, vaporisers vapes and shisha pens) are battery-powered devices that deliver nicotine by heating a solution of nicotine, flavouring, additives and propylene glycol and/or vegetable glycerine (glycerol).
The devices typically consist of a mouthpiece, battery and cartridge or tank containing the nicotine solution. When a user sucks on the device, a sensor detects air flow that activates a heating element, heating the liquid in the cartridge so that it evaporates.
Electronic cigarettes were developed to mimic the action of smoking, including nicotine delivery, without the toxic effect of tobacco smoke. For more information see ASH’s briefing on electronic cigarettes (http://www.ash.org.uk/files/documents/ASH_715.pdf).
Q How safe are electronic cigarettes, and how do the health risks associated with vaping and electronic cigarettes compare with smoking?
A Electronic cigarettes are relatively new products, and as such we do not know the impact of long-term use. However, the majority of experts agree that electronic cigarettes are much safer than smoking tobacco.
The harm from cigarette smoking is caused primarily through toxins produced by the burning of tobacco. By contrast, non-tobacco, non-smoked nicotine products, such a electronic cigarettes, are considerably less harmful. This means electronic cigarettes represent a safer alternative to cigarettes for smokers who wish to cut down or stop smoking.
Unlike combustible tobacco products, electronic cigarettes do not generate smoke and there is no secondhand smoke. The vapour emitted into the air, exhaled by the electronic cigarette user, generally comprises nicotine, aroma transporters, glycerol and propylene glycol.1
A 2014 review by Hajek et al, published in the journal Addiction, stated that: “Electronic cigarette aerosol can contain some of the toxicants present in tobacco smoke but at levels which are much lower. Long-term health effects of EC [electronic cigarettes] use are unknown but compared with cigarettes, EC are likely to be much less, if at all, harmful to users or bystanders.”1
Q What’s Public Health England’s view on the safety of electronic cigarettes?
A A 2014 review of the evidence commissioned by Public Health England (PHE) 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.”2
An Evidence Update commissioned by PHE in 2015 also reported that the amount of nicotine released into the ambient air poses no identifiable risk to bystanders.3 It stated that: “While vaping may not be100% 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 than tobacco smoking, but rather the specific estimate at how much less harmful.
Q Is much known about the chemicals used in electroni 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.4 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.”5
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.6
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.7
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.8
There are some flavourings where an element of risk is known and these flavours should be avoided. This includes some butterscotch or popcorn flavours which use diacetyl. Diacetyl has been associated with irreversible bronchiolitis known as “popcorn lung” in workers at a microwave popcorn plant.9
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.10
For more information see the National Centre for Smoking Cessation and Training (NCSCT) briefing on electronic cigarettes. (http://www.ncsct.co.uk/usr/pub/Electronic%20cigarettes.%20A%20briefing%20for%20stop%20smoking%20services.pdf).
Q Should the use of electronic cigarettes be time limited?
A Electronic cigarettes are relatively new products and, as already stated, we cannot yet know the impact of long-term use.
In contrast the dangers associated with long term smoking are well established. Every year tobacco is responsible for almost 80,000 deaths in England.11 It is the most important preventable cause of cancer, COPD and heart disease in the world, and half of all lifetime smokers will die prematurely as a result of their habit.12
Although nicotine is not the harmful component of smoking, according to NICE Guidance, there is reason to believe that lifetime use of licensed nicotine-containing products will be considerably less harmful than smoking,13 and in an ideal world people would stop using any form of nicotine. However, for those smokers who are unable or unwilling to remain nicotine free, electronic cigarettes are a preferable alternative to smoking.
It is also important to recognise that Office for National Statistics (ONS) data shows that over 700,000 ex-smokers are also former electronic cigarette users, indicating that people are using electronic cigarettes and going on to be nicotine free.14
Q How do electronic cigarettes approved for use by the NHS differ from those commercially available?
A At the time of writing no electronic cigarette product was available on the NHS. One product (E-voke) had received a Medicines and Healthcare
products Regulatory Agency (MHRA) medicinal licence and could be available on prescription at some point.
From May 2016 the regulation of electronic cigarettes will fall into two categories. Firstly, those that have a medicinal licence (such as E-Voke) and been approved by the MHRA. They will be able to make smoking cessation claims and may be available on prescription.
Electronic cigarettes which do not have an MHRA licence will be regulated under European law by the EU Tobacco Products Directive. These products must have less then than 20mg of nicotine per ml of liquid; they will not be able to make smoking cessation claims nor will they be available on prescription.
These products will also have to include health warnings on the packaging and manufacturers will have to notify the contents of their products to the
Q How effective are electronic cigarettes as a method of smoking cessation, and how does their success compare to other nicotine replacement therapies (NRTs)?
A ASH research shows that over 2.6 million people in Britain use electronic cigarettes. The most commonly reported reason for use is: “to help me stop smoking tobacco entirely”,15 which is consistent with ONS data.16 Recent studies have also found that electronic cigarettes have overtaken over-the-counter NRT as the first choice of stop smoking aid.
A monthly survey carried out by researchers from University College London estimates that in 2014 electronic cigarettes resulted in 20,000 more people quitting smoking who otherwise would not have done so,17 and recent evidence shows that electronic cigarettes are around 60% more effective in helping smokers quit than NRT bought over the counter or quitting ‘cold turkey’.18 In fact, the effectiveness of the devices as a quitting aid have been found to be broadly similar to using a prescription medicine (including NRT) with limited professional support.
A Cochrane Review that combined the results from two randomised controlled trials involving more than 600 people showed that using an electronic cigarette containing nicotine increased the chances of stopping smoking long-term compared to using an electronic cigarette without nicotine. About 9% of smokers using electronic cigarettes were able to stop smoking at up to one year compared with around 4% of smokers who used nicotine-free electronic cigarettes.19
In contrast, a US review which sought to assess the association between electronic cigarette use and smoking found that users of electronic cigarettes were less likely to stop smoking than smokers not using them as an aid to quitting.20 However, a number of experts have called it misleading and criticised the methodology of the review.21
Having said this, experts agree that more research is needed to better understand the circumstances in which electronic cigarettes are effective.
Meanwhile, the most effective way to quit smoking is by using an evidence-based stop smoking service that includes licenced smoking cessation medication and specialist behavioural support.
Q What types of smoking cessation products are available?
Q Is it recommended to combine different types of NRT?
A Yes. There is good evidence that using more than one NRT product at a time is more effective than single product use. Known as combination therapy, this method typically involves a nicotine patch plus a faster acting form of NRT such as gum, inhalator or nasal spray. Combination therapy might be particularly helpful for those who are highly dependent on nicotine, or who have found single forms of NRT inadequate in the past.
Varenicline (Champix) and bupropion (Zyban) should NOT be used or offered in combination.22 At present there is no specific indication for varenicline to be used with NRT. However, in practice it often is and there is no reason to believe it would pose a risk given that varenicline is licenced while smoking.
Q How safe is NRT in pregnancy? Can we prescribe varenicline or bupropion?
A Quitting smoking is one of the best things a woman and her partner can do to protect their baby’s health through pregnancy and beyond. Smoking during pregnancy can harm the baby in the womb from day one and risks include miscarriage, stillbirth, and sudden infant death syndrome (SIDS). All pregnant women who smoke should be encouraged and supported to quit.
NRT products are approved for use during pregnancy and it is considerably safer to use a licensed NRT product then to continue smoking during pregnancy. NRT can increase the chances of quitting successfully23,24 and this is especially true when combined with specialist help from local stop smoking services.
Nicotine patches should not be used for more than 16 hours in any 24-hour period, they should be removed at night, and if the patient is experiencing pregnancy-related nausea and vomiting, they should be avoided altogether.
Varenicline and bupropion should not be prescribed to women during their pregnancy or while they are breastfeeding.
Q What should we do when patients want long term NRT prescriptions?
The biggest problem with NRT is that people don’t use enough of it for long enough; patients should be encouraged to use it for at least 8-12 weeks. If someone is using nicotine long term, it is likely they would return to smoking without it. NICE guidance considers “stopping smoking, but using one or more licensed nicotine-containing product as long as needed to prevent relapse” - a recommend harm reduction approach”.26
NRT products have been demonstrated in trials to be safe to use for at least 5 years, whether it is used as a substitute for, or in combination with, cigarettes. Further results from a multicentre randomised controlled trial suggest that long-term use of NRT is not associated with an increased incidence of harm, including cardiovascular events or cancer, with the latest analysis of outcome at 12.5 years from study outset. 27
According to NICE guidance, there is reason to believe that lifetime use of licensed nicotine-containing products will be considerably less harmful than smoking.28
Q Are there any recommendations regarding the use of NRTs in patients with a history of mental ill health?
A Those with a long standing mental health condition are three times as likely to smoke as those without.
These people are also more likely to be heavily addicted to nicotine and may need more intensive and tailored support to quit. The good news is that people with mental health conditions are just as likely as other smokers to want to quit, and that what works for smokers in the general population works for mental health service users.
People with a mental health issue should be offered combination NRT. In fact, due to higher levels of nicotine dependence, the amount of NRT required by smokers with mental illness is likely to be higher than the rest of the population.
There are also no good grounds for excluding patients with mental health problems from taking varenicline. Because of its high level of effectiveness it may be their best chance of stopping smoking, especially given their generally high level of nicotine dependence.
While there have been some media reports of cases of suicide and suicidal thoughts in people taking varenicline, a 2015 meta-analysis found no evidence of an increased risk of suicide or attempted suicide, suicidal ideation, depression, or death with varenicline.25
However, bupropion is not recommended for smokers with a current or past history of seizures, current or previous diagnosis of bulimia or anorexia nervosa, or a history of bipolar disorder as it may precipitate a manic episode. There is also the potential for interactions between bupropion and psychotropic medicines (such as some antipsychotics and antidepressants).
For more information see the NCSCT briefing on smoking and mental health (http://www.ncsct.co.uk/usr/pdf/mental_health_briefing_A4.pdf).