Friday April 12 2013
Over 3 million e-cigarettes were sold in 2012
“Electronic cigarettes have helped almost nine out of ten smokers quit tobacco completely” the Metro reports. The claim is based on the results of an online survey on e-cigarette use and their effects on tobacco consumption.
The survey’s participants were mainly recruited via the websites of two leading manufactures of e-cigarettes.
The survey responses report an overall positive experience of e-cigarettes, for example:
- 75% of the sample said it had been several weeks or months since their last cigarette
- 91% said that use of the e-cigarette had ‘substantially decreased’ their craving for tobacco cigarettes
- 70% didn’t have as much of an urge to smoke
A significant limitation to the study is that the survey was self-selecting; people using the brand’s websites chose to take part.
It could be the case that people with a positive experience of using e-cigarettes were more likely to take part than people with negative experiences. So the results may not be representative. Also, the study did not assess whether these people actually quit smoking as a result of e-cigarette use.
This means the results cannot be compared to the effectiveness of stop-smoking treatments that have been properly tested and does not prove that e-cigarettes are an effective method of helping people to quit smoking.
Further research comparing e-cigarettes with other forms of ‘quitting tools’ (such as nicotine patches) in the form of a large randomised controlled trial or cohort study is required.
Where did the story come from?
The study was a cross-sectional survey carried out by researchers from the University of East London and was published in the peer-reviewed medical journal Addiction. The study received no sources of financial support.
The Metro’s headline that ‘Electronic cigarettes ‘help nine out of ten smokers quit tobacco completely’ appears to have been wrongly interpreted from the results of the survey.
While 91% of respondents said that use of the e-cigarette had ‘substantially decreased’ their craving for tobacco, a reduction in craving, while helpful, does not necessarily mean a person has successfully stopped smoking.
The Metro also failed to highlight the inherent limitation of the study (which the researchers flagged up in their conclusion). That is, a cross sectional self-selecting survey, such as this, is unable to provide evidence on the effectiveness of e-cigarettes for helping smokers to quit.
What kind of research was this?
Electronic cigarettes are battery-operated devices that deliver variable quantities of nicotine via inhaled vapour. The process of smoking an e-cigarette mimics smoking a tobacco cigarette and is sometimes referred to as ‘vaping’. The market for e-cigarettes has been increasing every year since their introduction in 2004, with 3.5 million sold in 2012.
There is currently said to be a lack of trial data on e-cigarettes, though three published studies have suggested they can provide moderate relief of craving and withdrawal symptoms.
Much more research is also said to be needed on the nature of e-cigarette use, including:
- who uses them
- how effective they are for quitting/harm reduction
- how safe they are
- how addictive they are
The current study is a cross sectional survey which aims to characterise the use of e-cigarettes and their effects in a sample of users of the Electronic Cigarette Company (TECC) and Totally Wicked E-Liquid (TWEL) brands. These two brands are widely used in the UK.
The survey recruited participants via the brands' websites and was hosted on the University of East London’s website.
As a cross sectional sample of a specific population group, this study is a start for research into these products, but can only tell us the experiences of people, who chose to take part in the survey, at one point in time.
It cannot reliably tell us how effective e-cigarettes are in helping smokers to quit nicotine or smoking, or whether e-cigarettes are a better alternative to ‘traditional’ nicotine replacement therapies (NRTs) such as patches or gum.
What did the research involve?
People were recruited from the TECC and TWEL websites and online survey data was collected between September 2011 and May 2012. The questionnaires were completed by 1,347 people from 33 countries (72% European). They had an average age of 43 years, 70% were male and 96% were of white ethnic origin.
The questionnaire was described as taking 15-20 minutes and covered six areas:
Current smoking status
- current smoker
- never-smoker (fewer than 20 cigarettes in your lifetime)
Pattern of tobacco smoking
This was assessed using a validated ‘checklist’, designed to assess levels of cigarette dependence, known as the Fagerström Test of Cigarette Dependence (FTCD).
This involves questions such as “How soon after waking do you/did you smoke your first cigarette?” and “Do you find it difficult to refrain from smoking in places where it is forbidden?”
Similar adapted questions were used for ex-smokers, who were also asked about the length of time since stopping.
Pattern of e-cigarette use
- length of use
- product and cartridge type
- strength and preferred flavours
- amount used (in ml and puffs; where participants indicated a range, maximum daily use was used)
- reasons for use (such as a complete or partial alternative to smoking)
- dependence on the e-cigarette and attempts to cut down use
Personal experience of e-cigarette use
- satisfaction and ‘hit’
- acceptability by others
- effects on craving
- impact on smoking behaviour
- respiratory effects
- whether a person experienced any side effects when using an e-cigarette
Results were analysed separately for the full sample (which included four never-smokers who used the e-cigarette), and separately for ex-smokers (1,123) and current smokers (218), and for males (897) and females (390).
What were the basic results?
A total of 1,347 participants (98% of the sample) had filled in enough survey data to be used in the analysis. Average duration of e-cigarette use was 10 months.
Most people heard about the e-cigarette from the internet, followed by personal contacts. Almost half the respondents (49%) used the e-cigarette within six to 30 minutes of waking and 23% used within five minutes of waking. Ex-smokers reported using the e-cigarette sooner after waking than current smokers, used higher amounts daily, and had also been using the e-cigarette for longer.
Over half of all respondents (56%) replied ‘yes’ to the question ‘Do you use the e-cigarette in the same manner as cigarettes?’. Seventy-six percent of the whole sample reported that they had started using the e-cigarette as a complete alternative to smoking, and 22% stated ‘other reasons’, which included to quit smoking and for health reasons.
Three-quarters of the whole sample said that they had not smoked for several weeks to months since using the e-cigarette and 14% said their cigarette use had dramatically decreased (with ex-smokers answering more affirmatively to these questions). The majority (91%) said that use of the e-cigarette had ‘substantially decreased’ their craving for tobacco cigarettes. Seventy percent said they don’t have the urge to smoke so much anymore.
Overall satisfaction with the product was high, with the majority of the sample reporting that e-cigarette use feels healthier to them and has helped their breathing.
Though males and females differed in some aspects, such as type of e-cigarettes used (for example, women preferring chocolate/sweet flavours), there were no differences in their responses on reasons for use or the effects.
Fewer than 16% of all participants reported any adverse effect of e-cigarettes. The most common was throat irritation.
How did the researchers interpret the results?
The researchers conclude that e-cigarettes are used primarily as an alternative to smoking and that most found that e-cigarette use has helped reduce their craving and substantially reduce their tobacco use. Most users also found them satisfying to use and believe them to be safer and healthier than smoking.
This cross sectional survey of 1,347 people who were recruited via the Electronic Cigarette Company (TECC) and Totally Wicked E-Liquid (TWEL) brands' websites – the two brands most widely used in the UK – finds an overall positive experience on the use of e-cigarettes.
The majority of the sample had started using the e-cigarette as an alternative to smoking, a smaller number used them to help them quit smoking.
Three-quarters of the sample said that it had been several weeks to months since their last cigarette, 91% said that use of the e-cigarette had ‘substantially decreased’ their craving for tobacco cigarettes, and 70% didn’t have as much of an urge to smoke.
These are positive results for the marketers of e-cigarettes, but the most important thing to remember is that this is a cross sectional sample that can only tell us the experiences of a specific population group – people who were recruited from two e-cigarette brand websites.
As they were already using e-cigarettes and chose to take part in the survey it is possible that this sample is over-representative of people who have found e-cigarettes to be beneficial.
We do not know what the experiences and effectiveness would be in a wider sample of smokers from the general population who tried e-cigarettes.
Overall, the study reports on the positive experiences of a large sample of users but no conclusions on the effectiveness of e-cigarettes in helping smokers to quit can be made from this study. This is not to say that e-cigarettes are ineffective, but rather, the study in question cannot provide a definitive answer one way or the other.
The best way to evaluate the effectiveness of e-cigarettes would be to conduct a randomised controlled trial comparing the effectiveness of e-cigarettes with a sham alternative. However, it is likely to be difficult to blind such a trial, meaning that people would be aware whether they were using the e-cigarette or not which would be a limitation of such a trial.
An alternative that would help to shed more light on this issue would be a carefully conducted cohort study which followed people using the e-cigarette over time to see how many of them were successfully able to quit, and what other things were associated with success (such as number or prior quit attempts, duration of past smoking habit, etc).
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.