There is increasing research into e-cigarettes but at present the evidence base for their safety, quality and efficacy is not extensive. In 2013, the World Health Organisation (WHO)26 stated, ‘the safety of ENDS has not been scientifically demonstrated’ and ‘the potential risks they pose for the health of users remain undetermined’. This concurs with the findings of the MHRA, which recently completed market and scientific research of NCPs including e-cigarettes. They concluded that, ‘although there is no evidence to suggest that using electronic cigarettes is more harmful than smoking tobacco cigarettes there remains a paucity of scientific evidence on the long-term effects’.16
In addition to the undetermined long-term safety concerns of the effect of e-cigarettes on health, variations have been found in the quality of the e-cigarette products in relation to the ingredients of the e-liquids, which could vary in nicotine concentration within the same batch; could contain additional additives and contaminants; and could vary in the effectiveness of nicotine delivery from devices.16 Concern was raised at a recent European Commission27 meeting by two e-cigarette associations that ‘there were still quality and safety issues with some products and that not all producers of electronic cigarettes were ‘responsible’ manufacturers’.
Although the safety of e-liquids for both short-term and long-term health requires further research, ASH5 has stated that ‘they are likely to be a safer alternative to smoking’. In a study of 20 tobacco cigarette smokers who substituted tobacco cigarettes with e-cigarettes for 2 weeks all the tobacco smoke toxins tested for were substantially reduced.28 A study on vapour produced from 12 brands of e-cigarettes, which analysed toxicants normally found in tobacco cigarette smoke, found that the toxicants (some of which were carcinogenic) examined for were present, but at a ratio of 9 to 450 times less than in tobacco smoke.29 Another study found that exhaled vapour produced from three models of e-cigarettes contained nicotine and that people in close proximity would be exposed to the nicotine but it would be at levels ten times lower than nicotine from tobacco cigarette smoke.30
While the use of ‘e-cigarettes may be useful in reducing the harm of cigarette smoking in those unable to quit’28 it ‘may involuntarily expose non-users to nicotine’.30
Nicotine is an addictive substance and can be toxic, however, studies on NRT have not found nicotine to be implicated in cardiovascular disease31 or in cancer.32 While tobacco is known to be harmful to periodontal health,33 nicotine itself may be implicated in adverse effects on the periodontium through various mechanisms such as peripheral vasoconstriction.34
The efficacy of e-cigarettes in smoking cessation
Quitting smoking by stopping abruptly or by gradual reduction with or without aids such as nicotine replacement therapy (NRT) and/or support35 has has until the 2013 National Institute for Care and Health Excellence (NICE) guidance on tobacco harm reduction,36 been the main approach to reducing tobacco consumption.
The STS9 showed that the percentage of smokers attempting to stop smoking in 2013 ranged from 29–36% and smokers trying to quit who used support in the form of smoking cessation services, over the counter NRT or medical prescriptions were increasingly using e-cigarettes to support their quit attempt. The efficacy of e-cigarettes as a smoking cessation tool has yet to be scientifically demonstrated26 but anecdotal findings from newspaper articles15 and comments from online newspaper threads indicate that some users are reporting that use of e-cigarettes has enabled them to quit smoking tobacco.
A recent randomised control study by Bullen et al.37 investigating quit rates using e-cigarettes and nicotine patches over a 6 month period, found that there was no statistically significant difference between the quit rate in the group using e-cigarettes delivering nicotine (quit rate 7.3%), compared with the group using nicotine patches (quit rate 5.8%). An additional finding from the study was that, at 6 months, 57% of those in the e-cigarette delivering nicotine group had reduced their tobacco consumption by half or more.
The efficacy of e-cigarettes in harm reduction
Harm reduction may be defined as ‘the long-term use by smokers of less harmful non-tobacco products, with or without a quit attempt’.38 The recent NICE guidance on Tobacco harm reduction approaches to smoking36 advises that a tobacco harm reduction approach may be helpful for people who:
May not be able to stop smoking (or do not want to stop) in one step
May want to stop smoking, without necessarily giving up nicotine
May not be ready to stop smoking, but want to reduce the amount they smoke.
A broad range of harm reduction strategies are advised, including the use of NRTs, which are licenced nicotine products. E-cigarettes are not licenced as NRTs and because at present their safety, quality and efficacy cannot be assured, they are not recommended. Products on the market that are regulated as medicines, and mimic the hand to mouth action of smoking, are inhalators for example, Nicorette, NicAssist. The inhalators do not have an atomiser and the liquid nicotine concentration is 15 mg/ml.
Surveys are showing that, despite e-cigarettes not being recommended as a harm reduction approach, there is an increasing use of e-cigarettes by smokers to help them reduce the amount of tobacco they smoke,10 with 10% of smokers now using them as a harm reduction measure and this has overtaken NRTs.9
Evidence of e-cigarettes as a ‘gateway’ to tobacco use
There are concerns that the use of e-cigarettes containing nicotine, a highly addictive psychoactive drug, may act as a ‘gateway’ to the use of tobacco products by those who have never smoked.39,40 Some argue that it is preferable for those who decide they may wish to smoke to choose e-cigarettes rather than tobacco cigarettes.41 At present the surveys in the UK have shown that there is little uptake of e-cigarettes by children or those who have never smoked,10 but the de Andrade et al.2 report found marketing strategies targeted two groups: the committed smoker, who may think about quitting; and the younger social smoker and non-smoker. It may be too early in this emerging market to find evidence of e-cigarettes as a ‘gateway’ to smoking.
Evidence of vaping renormalising smoking
Smoking was a social norm in the UK in the 1950s and 1960s, advertised widely and allowed in public places, on transport and often in the workplace. The comprehensive range of tobacco control measures introduced gradually over recent years has meant that many of those in their early 20s today have grown up without the same exposure to smoking behaviours as experienced by their parents/carers or grandparents. There is a concern that vaping, which mimics smoking behaviour and is being widely advertised and allowed anywhere (unless banned) may renormalise smoking.38,42 Distinguishing between vaping and smoking may be obvious for some but not for others, for example, children43 – it may be difficult to police and it may be too early for research to establish if, or how, vaping changes the perceptions of smoking.