Printed on: June 22nd, 2025

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Smoking, smoking cessation and e-cigarettes

Smoking, smoking cessation and e-cigarettes

If we had to pick a single thing that would have the greatest impact on cancer rates, stopping smoking would be our top choice. It has about 4 times the impact on cancer deaths of any other single lifestyle intervention, not to mention the benefits for other big killers such as ischemic heart disease and COPD. Tobacco smoking is the leading cause of preventable disease, disability and death (US Public Health Service Office of the Surgeon General, 2020).

Although smoking rates are falling in the UK, one in six adults smoked regularly in 2019 (BMA, 2022). Globally in 2020, one-third of males and 8% of females (over age 15y) smoke (Lancet 2021;397:2337, WHO 2023).

Worldwide, tobacco kills over 8 million people annually, with around 1 million of those via passive smoking. Tobacco kills up to half of its users who don’t quit according to the WHO (WHO, 2023), or up to two-thirds of long term users according to the UK Government (gov.uk, 2024).

Brief intervention can help. We’re busy and short of time, but raising the issue and offering advice takes only a few seconds. If you want to learn how to do this in a brief, effective way, the National Centre for Smoking Cessation and Training offers free educational resources for you and your staff.

Consider also reading our article Motivating behaviour change, which may help guide your discussions.

This article was updated in April 2025. Thank you to Professor Nick Hopkinson for his review of this article.

In 2007, the World Health Organisation introduced MPOWER, a global strategy to tackle tobacco use:

• Monitor tobacco use and prevention policies.
• Protect people from tobacco use.
• Offer help to quit tobacco use.
• Warn about the dangers of tobacco.
• Enforce bans on tobacco advertising, promotion and sponsorship.
• Raise taxes on tobacco.

There is no simple, single answer! It’s thought to be a combination of genetic, social, environmental and behavioural factors. We know that certain things increase the likelihood of smoking:

• Smoking households: children whose parents smoke are 4 times as likely to take up smoking themselves (UK Department of Health, 2021).
• Low socioeconomic status: smoking is more common in those with lower incomes (ASH Health Inequalities and Smoking, 2019).
• Mental illness or previous substance abuse (J Clin Psychiatry 2017;78:e152).
• Peer pressure (Thorax 2019;74:607).
• Advertising (Cochrane Database Syst. Rev. 2003;CD003439).

Nicotine is highly addictive and activates the brain’s dopamine-mediated reward system (Annu Rev Pharmacol Toxicol. 2009;49:57). Withdrawal can cause depressed mood, anxiety, frustration, increased appetite and weight gain.

Although addictive, nicotine is not the major harm in cigarettes – rather, this comes from the thousands of other toxins, including tar and carbon monoxide. Nicotine acts as the anchor, altering the behaviour of the addicted individual to repeatedly consume a trojan-horse full of toxins.

Thus, nicotine-replacement therapies (NRTs) allow us to separate the nicotine from the toxins, and administer one without the other. In the UK, NRT is available as patches, gum, inhalators, tablets, nasal spray and mouth spray (NHS – stop smoking treatments).

NICE suggests that we make the following smoking-cessation interventions available to those aged 12y and over (NICE 2023, NG209):

• Behavioural interventions, including brief advice, group and individual behavioural support.
• Buproprion (from age 18y).
• Nicotine replacement therapy.
• Varenicline (Champix) (from age 18y). Withdrawn from the UK market due to it containing nitrosamines (see MHRA alert, 2021) (NICE 2007, TA123). Reintroduced to the market in late 2024 (by Teva, as a generic) (National Centre for Smoking Cessation and Training).
• Nicotine-containing e-cigarettes.
• Allen Carr’s Easyway in-person group seminar.
• For adults, provide buproprion, varenicline or NRT before they stop smoking.

See the BNF for further prescribing information.

There is strong evidence that the best chance of a successful quit attempt results from a combination of behavioural support from ‘stop-smoking’ services combined with pharmacological aids, i.e. NRT (including e-cigarettes), varenicline or buproprion (UK Department of Health, Health Matters: stopping smoking – what works). Using this strategy is four times more likely to work than trying to stop unaided or using over-the-counter NRT.

A drug with 2 names, cytisine/cytisinicline has been around for years. NICE uses the name cytisine but the BNF goes for the longer, less pronounceable version, cytisinicline. We are aligning with NICE because cytisine is easier to type.

Cytisine has been used successfully for decades in eastern Europe and Russia as a smoking cessation aid. It was smoked by soldiers during WW2 as a cheap tobacco substitute. It comes from the laburnum tree (BMJ 2013;347:f5198).

Cytisine was approved by the MHRA in 2019, but didn’t come to market until 2024.

Yes! A Cochrane network meta-analysis suggests that cytisine is probably better than buproprion, and similarly effective to varenicline and e-cigarettes (Cochrane Database Syst Rev 2023:CD015226). NICE published an ‘exceptional review’ in February 2024 in which it recommended that cytisine be considered alongside other options for smoking cessation (NICE 2024, NG209).

The DTB provides a useful overview (DTB 2024;62:71).

• Cytisine has a similar structure to nicotine, acting on nicotinic receptors as a partial agonist (like nicotine, but weaker).
• Cytisine also increases dopamine in the brain, helping alleviate some central symptoms of nicotine withdrawal.
• Cytisine stimulates adrenal catecholamines, helping some peripheral symptoms of nicotine withdrawal.

• A 1.5mg tablet taken every 2h over the first 1–3 days, then reducing in frequency of administration over the course of a month.
• Licensed for adults aged 18–65y (note upper age limit).
• Smoking is stopped no later than day 5 of treatment.
• Cytisine is contraindicated after recent MI or recent stroke (the BNF or SPC does not define a time period for ‘recent’), in unstable angina or in those with arrhythmias (we assume this includes AF) (BNF, accessed June 2024).
• Highly-effective contraception is required during treatment for females with childbearing potential. Avoid in pregnancy and while breastfeeding.

It is estimated that 5.6 million people in the UK use e-cigarettes (ASH, August 2024).

E-cigarettes have a battery-powered heating element that heats a solution containing nicotine to create an aerosol that can be inhaled (‘vaping’). There is no combustion so there is no smoke, no tar and no carbon monoxide.

We can think of e-cigarettes as those which contain nicotine and those which do not:

• Products containing nicotine are regulated under the Tobacco and Related Products Regulations (2016). They are notified to the MHRA and are limited to 20mg/ml nicotine.
• Vaping products that do not contain nicotine are regulated under the General Product Safety Regulations (2005).

The device itself may be single-use (disposable) or refillable (pod and cartridge).

E-cigarettes contain plastics and metals, including a lithium battery. Disposable devices are single use, lasting around 600 puffs, and have an associated carbon footprint. Discarded e-cigarettes are increasingly visible as litter in the community and countryside. It’s important that these devices are disposed of through WEEE recycling (waste electrical and electronic equipment) rather than ending up in landfill, incineration or as environmental litter (Am J Public Health 2018;108:1489, FSDA).

Refillable, reusable devices are less harmful to the environment. In January 2024, the UK Government announced its intention to ban disposable vapes. The implementation date is 1 June 2025.

Vaping poses only a small fraction of the risks of smoking (OHID, 2022).

• The risk to bystanders is thought to be negligible.
• The cancer risk associated with vaping is quoted as less than 0.5% of the risk associated with smoking.
• Changing from smoking to vaping gives substantial health benefits.

A 2015 PHE statement estimated that e-cigarettes were “95% less harmful” than smoking. This statement was upheld in 2022 as being “broadly accurate” following criticism of the methodology involved in the formulation of the 95% figure (2022 OHID report, Lancet 2015;386:829).

The exact figure doesn’t really matter: the clear conclusion is that e-cigarettes are substantially less harmful than tobacco, but not risk free.

The following organisations support the promotion of e-cigarettes to current smokers as a part of a smoking cessation strategy:

• The Royal College of Physicians.
• NICE.
• British Thoracic Society.
• RCGP and Cancer Research UK (joint statement).
• UK Health Security Agency (UKHSA – formerly Public Health England (PHE)).

Yes.

Of note: e-cigarettes can’t be marketed as a smoking cessation aid because this would be a medicines claim, which would require MHRA licensing. There are currently no licensed medicinal e-cigarettes, but the MHRA has indicated that it would facilitate licensing.

Show me the evidence:

• A Cochrane review stated that there is “high-certainty evidence that e-cigarettes with nicotine increase quit rates compared to NRT and moderate-certainty evidence that they increase quit rates compared to e-cigarettes without nicotine” and “overall incidence of serious adverse effects was low across all study arms.” (Cochrane Database Syst Rev. 2024;1:CD010216)
• A UK-based RCT found that e-cigarettes were more effective than NRT (NEJM 2019;380:629). An e-cigarette proved twice as effective as a combination of NRT products.
• A Swiss trial randomised over 1200 smokers to an intervention arm (free e-cigarettes, plus counselling, plus option ‘to purchase’ nicotine replacement therapy) or a control arm (counselling plus a voucher which could be used for any purpose, including nicotine replacement therapies) (NEJM 2024;390:601).
  • Quit rates at 6 months (the primary outcome measure) were 28.9% in the intervention group vs. 16.3% in the control group.
  • Interestingly, despite the success, the rates of nicotine abstinence were 20% in the intervention group vs. 34% in the control group because people tended to continue to use their e-cigarettes.
  • An associated editorial concludes that “it is now time for the medical community to acknowledge this progress and add e-cigarettes to the smoking-cessation toolkit” (NEJM 2024;390:664).

The UK Government stance:

• NICE recommends the use of nicotine-containing e-cigarettes as a smoking cessation measure (NICE 2023, NG209).
• Public Health England ‘Evidence review of e-cigarettes and heated tobacco products, 2018’ stated that e-cigarette use is associated with improved quit success rates (up to 20 000 successful new quits/y) and an accelerated decline in smoking rates in the UK.

The National Centre for Smoking Cessation and Training offers us some advice when discussing e-cigarettes with patients:

• Be positive when talking about e-cigarettes for smoking cessation.
• Don’t push people to come off their e-cigarette.
• Don’t be alarmed about ongoing use of recreational nicotine (although addictive, the nicotine itself isn’t particularly harmful, and we’re not a ‘stop-nicotine’ service!).

Next, let’s look at the harms. A review of 17 systematic reviews, which included 5 meta-analyses, identified adverse effects from e-cigarettes, including increased heart rate, increased BP, oxidative stress and airflow obstruction (Int J Environ Res Public Health 2022;19:9054). For non-smokers, there are no benefits from vaping (JAMA 2024;332:709).

If e-cigarettes are used for smoking cessation, it is important that they COMPLETELY replace tobacco smoking. This is because continued tobacco use PLUS e-cigarettes is not an effective harm-reduction intervention due to the ongoing risk associated with even a small number of tobacco cigarettes (JAMA 2024;332:751). Smoking even ONE cigarette per day is sufficient to significantly increase coronary heart disease and stroke risk (in fact, 1-per-day confers around 50% of the risk of 20-per-day) (BMJ 2018;360:j5855). In 2024, just over 1 in 20 adults in England smoked cigarettes AND vapes, an increase from around 1 in 30 in 2016; however, there has been a shift in dual users from more frequent smoking towards more frequent vaping (Addiction 2025;120:608).

It is likely that it will take 10–20y before there is enough long-term epidemiological data to fully answer the questions about risks and safety (BMJ 2019;366:l5445).

The bottom line: our priority is harm reduction; we should support and promote e-cigarette use in preference to tobacco smoking, but not promote it to non-smokers!

The WHO states that e-cigarettes “should not be promoted as a cessation aid until adequate evidence is available and the public health community can agree upon the effectiveness of those specific products”. It states that “e-cigarettes do not contain tobacco but are harmful to health and are not safe”. It points out that:

• E-cigarettes increase the risk of heart disease and lung disorders.
• There is a significant risk to pregnant women who use them because they damage the foetus. (However, e-cigarettes are much safer than smoking in pregnancy, and the overall safety is comparable to nicotine patches, NIHR 2022.)

Although supportive of their use, the Royal College of Physicians has stated in the past that, because e-cigarettes are not currently made to medicines standards, they are “probably more hazardous than NRT” (BMJ 2018;360:j5543).

In e-cigarette or vaping-associated lung injury (EVALI), patients present with a combination of symptoms (BMJ 2019;366:l5445):

• Respiratory: cough, shortness of breath, chest pain.
• Gastrointestinal: nausea, vomiting, diarrhoea.
• Systemic: fever, fatigue, weight loss.

The MHRA suggests that EVALI is probable if ALL the following criteria are met:

• Using an e-cigarette/vaping in the 30d before symptoms started AND
• Pulmonary infiltrate, e.g. opacities on chest X-ray or ground glass on CT chest, AND
• No evidence of alternative diagnosis (e.g. cardiac, autoimmune, cancer) AND
• Absence of respiratory infection:
  • Negative respiratory viral screen (e.g. influenza, adenovirus, rhinovirus, coronavirus) AND
  • Negative testing for all other clinically-indicated respiratory infectious diseases (sputum culture, urine for Strep. pneumoniae and Legionella, blood culture, bronchoalveolar lavage culture and testing for opportunistic respiratory infections if appropriate).

This definition relates to pulmonary infiltrate in the absence of another cause (rather than specific clinical symptoms). We are not going to be making the diagnosis in primary care, but rather referring if we have concerns.

The 2019 US EVALI outbreak:

In 2019, there was an outbreak in the USA of 2600 cases of EVALI and 68 associated deaths.

Retrospective product testing by the FDA concluded that the outbreak was likely due to vitamin E acetate added to cannabis products (a bad batch). The substance was also present in lung fluid samples tested by the CDC. Vitamin E acetate was not found in the lung fluid of healthy e-cigarette users. Vitamin E acetate is banned from UK regulated e-cigarettes.

In January 2020, the MHRA issued an update on e-cigarette use in the UK. At that time, there had been 244 suspected adverse reactions to e-cigarettes/vaping reported to the MHRA, with 182 related to respiratory symptoms. There have been 2 potential cases of e-cigarette or vaping-associated lung injury (EVALI) reported in the UK, both of which were fatal (MHRA, Drug Safety Update Jan 2020).

The MHRA asks us to:

• Maintain a high index of suspicion in patients presenting with respiratory symptoms in the 30 days following e-cigarette use or vaping.
• Report suspected e-cigarette side-effects through the Yellow Card scheme.
• Ask all patients about e-cigarette use and vaping routinely, in the same way we would with cigarette smoking.

Selling e-cigarettes to under 18-year-olds is illegal.

We have discussed the pros and cons of nicotine-containing e-cigarettes in current smokers, but there are clear concerns about the rising use in ‘never-smokers’, especially young people:

• Does the availability and promotion of e-cigarettes increase uptake of vaping?
• Do we fully understand the impact of this on developing lungs?
• Do e-cigarettes increase their chances of starting to smoke cigarettes?

Rates of vaping in children and young people are increasing.

According to UK Government data, the incidence of vaping in young people aged 11–17y in England increased from 3.3% in 2021 to between 9 and 14% in 2022. By 2023, almost a quarter of 18-year-olds reported long-term vaping (BMJ 2024;386:e079016, Nicotine Vaping in England: 2022 evidence update main findings, NHS Digital; Smoking, Drinking and Drug Use among Young People in England, Office for Health Improvement and Disparities 2022).

An editorial in the BMJ expressed significant concern that:

• Devices commonly used by young people contain a significant amount of nicotine, which leads to addiction.
• Adverse effects of nicotine in adolescents include attention deficit, mood disorder and suicidal thoughts. Nicotine addiction is more likely in young people, with a potential lifelong impact.

It also commented that the UK has a less cautious approach to promotion of e-cigarettes than many other countries. For example, in the USA, many states have banned flavoured vape liquids, and the FDA regulates e-cigarettes in an equivalent manner to the regulation of cigarettes (BMJ 2022; 379:e073824).

Apparently not. Data from several studies suggests that there is no association between the prevalence of vaping and the prevalence of smoking in England. This applies to both young people and to the adult population (BMJ 2024;386:q1508). Higher vaping rates have not translated into higher smoking rates. That said, the net effect seems to be an increase in total nicotine use in young people.

The Tobacco and Vapes Bill began its journey through Parliament on 5 November 2024. Key aims:

• Flavour and packaging restrictions to reduce appeal to young people.
• Vape advertising and sponsorship bans.
• Banning smoking and vaping in certain public spaces such as playgrounds and school entrances (subject to consultation).
• On-the-spot fines.
• Raise the minimum age for buying tobacco by one year every year, which will effectively make it illegal for anyone born after 1/1/2009 to ever purchase tobacco legally in the UK.

Disposable vapes are due to be banned from 1 June 2025 under environmental legislation.

Our primary concern is smoking cessation, but an emerging issue is how to help those wishing to stop nicotine-containing e-cigarettes. Smoking cessation followed by vape cessation should be the goal in order to minimise potential harm.

In personal communication with Red Whale, Nicholas Hopkinson (Professor of Respiratory Medicine, Imperial College) offered this excellent advice: “If someone has switched from smoking to vaping, they should be told that they have made a big step to reduce their health risk, but should be advised to quit vaping too if they can eventually, but not at the expense of going back to smoking.”

Nicotine is very addictive, even if not particularly harmful. For those who wish to stop vaping, this addiction can pose a major challenge. We covered cytisine for smoking cessation earlier in this article, but does it work for those wishing to quit nicotine-containing e-cigarettes? Logic says yes, but is there any evidence?

A double-blind placebo-controlled trial randomised 190 patients to 12 weeks of cytisine or 12 weeks of placebo. Both groups received behavioural interventions (JAMA Intern Med 2024 May 6:e241313).

• 32% quit vapes in the cytisine group.
• 15% quit vapes in the placebo group.
• 4% discontinued cytisine due to adverse reactions.

This small trial demonstrated efficacy. Larger trials are needed.

Note that cytisine is not licensed for this indication in the UK.

A double-blind randomised trial performed on 1500 adolescents (recruited by social media) of a text message to encourage vaping cessation in adolescents found higher rates of abstinence in the intervention group than the control group (JAMA 2024;332:713).

It’s never too late to stop smoking (Nature, 2020;578:266). Ex-smokers have four times more genetically healthy cells than smokers.

Quitting at any age has a large impact on death rates from ALL smoking-related diseases. Nearly all excess risk is avoided if smoking stops before age 40y. Quitting is MUCH more effective than cutting down (NEJM 2013, 368:351).

• 4 in 10 smokers and ex-smokers mistakenly believe that nicotine is the cause of most of the smoking-related cancers (NONE are caused primarily by nicotine) (UKHSA, 2018).
• Most smoking-related problems are caused by the toxins in tobacco smoke, rather than the nicotine (NICE 2023, NG209).

Nicotine causes the addiction, but the other chemicals in cigarettes cause the damage. Nicotine itself carries minimal risk to health in adults (NHS – vaping myths and the facts, accessed November 2024).

A paper in the Journal of the American Heart Association found that same-day and every-day e-cigarette use was associated with having had a myocardial infarction (JAHA 2019;8:e012317). Flawed methodology eventually led to retraction of the paper because the methods did not account for the possibility of the MI predating e-cigarette use (JAHA 2020;9:e014519).

A subsequent high-quality, prospective RCT found that switching from cigarettes to e-cigarettes significantly improved vascular health within one month of the switch. The authors concluded that this was a useful harm-reduction measure (J Am Coll Cardiol 2019;74:3112).

In 2020, only 1 in 3 adults in England knew that e-cigarettes are far less harmful than cigarette smoking (UKHSA 2020). In 2015, the then Public Health England stated: “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”.

We know that passive smoking is harmful, resulting in 1 million deaths worldwide. However, the UKHSA 2018 report did not find any evidence of harm to bystanders because there is no side-stream vapour (just exhaled aerosol).

Popcorn lung got its name after the condition was found in workers at a popcorn factory. Technically, it’s bronchiolitis obliterans, which can be caused by high levels of exposure to diacetyl. Historically, internationally, some flavourings in e-liquids contained diacetyl, although it has been banned in the UK since at least 2016. Diacetyl is present in much higher levels in cigarette smoke (CMAJ 2019;191:E1319).

These products are subject to legislation that regulates their quality and safety.

• Products containing nicotine are regulated under the Tobacco and Related Products Regulations (2016). They are notified to the MHRA and are limited to 20mg/ml nicotine.
• Vaping products that do not contain nicotine are regulated under the General Product Safety Regulations (2005).

E-cigarette use appears to be associated with reduced tobacco use. They help people quit and appear to be contributing to reduced smoking rates (NCSCT, 2024).

Some of you have contacted us with queries about e-cigarettes and smoking cessation.

Nicotine suppresses appetite, and some people put on weight when they stop. This is likely due to increased calorie intake after appetite suppression stops. Not everyone who stops smoking will gain weight. A meta-analysis found that smoking cessation results in a mean weight increase of 4–5kg at 12 months, but around 16% LOSE weight while 13% gain over 10kg (BMJ 2012;345:e4439).

E-cigarettes are not included in QRISK3 because the huge datasets used in creation of QRISK3 did not include e-cigarettes as a variable in the analysis (BMJ 2017;357:j2099). The smoking status variable included non-smoker, former smoker, light smoker, moderate smoker or heavy smoker.

More broadly, there is insufficient data to prove that e-cigarettes are an independent causative risk factor for CVD. There is an association between e-cigarettes and CVD, but most trials are confounded by the fact that people who vape often smoke or are ex-smokers.

Some trials suggest that cardiovascular risk is higher in those who currently smoke AND vape when compared with current non-vaping smokers (Am J Med 2019;132:949).

Ideally, we need good long-term data on people who vape, but have never smoked (Circulation 2022;145:1557). At this point, data indicates that e-cigarettes are far less risky than smoking tobacco, which is a known significant harm. Cardiovascular risk calculation is always evolving (QR4 is on the horizon) so watch this space.

UK medical eligibility criteria (UKMEC) from the FSRH (2019) does not have a category for vaping. The FSRH Clinical Effectiveness Unit recommends that vape users be treated the same as smokers. See our article Contraception, smoking and e-cigarettes for more information.

Possibly, but not as harmful as smoking tobacco. As we’ve already discussed, vaping is not risk free, and this extends to oral health. The evidence base to quantify risk is limited. However, because smoking is a key risk factor in many oral health conditions, including oral cancers, the message remains the same: vaping is safer than smoking, and ‘not vaping’ is safer than either vaping or smoking (J Dent Res 2021;100:906).

Smoking, smoking cessation and e-cigarettes Smoking rates are falling, but around 1 in 6 adults in the UK smokes regularly. Stopping smoking is the single most effective thing you can do for your health. We are in a position to offer brief intervention: don’t miss this chance! Nicotine, while highly addictive, is not particularly harmful. NICE recommends a range of counselling and pharmacological approaches, including e-cigarettes. E-cigarettes are far less harmful than tobacco-containing products.

Useful resources: Websites (all resources are hyperlinked for ease of use in Red Whale Knowledge) NHS stop smoking services Action on Smoking and Health (ASH) The National Centre for Smoking Cessation and Training (offers free training)