More research is needed into the effectiveness of electronic cigarettes (e-cigarettes), although emerging research suggests the method is an effective way to reduce or quit smoking, according to a review of research on e-cigarettes conducted by the Cochrane Library.

The Cochrane Library is a collection of six research databases that contain different types of high-quality, independent evidence to inform healthcare decision-making, and a seventh database that provides information about groups in The Cochrane Collaboration.

The first Cochrane review on this subject published in December 2014 in the Cochrane Library gives some early insights into electronic cigarettes as an aid to stopping smoking and reducing consumption.

The Cochrane review drew on two randomised trials and found that while nicotine containing electronic cigarettes were more effective than electronic cigarettes without nicotine (placebo) in helping smokers kick the habit, the results need to be confirmed by more studies.

Smoking is a major global health problem, is costly and is highly addictive. Despite many smokers wanting to stop, few succeed in the long-term. One of the most widely used strategies to help combat the cravings associated with nicotine addiction is to deliver nicotine by patches and chewing gum.

About e-cigarettes

Electronic cigarettes, also known as e-cigarettes, personal vaporizer (PV) or electronic nicotine delivery system (ENDS), are used to supply nicotine to a user without the burning of tobacco leaves. Use of e-cigarettes is often referred to as “vaping”. E-cigarettes work through the production of a vapour from a liquid which contains the nicotine and other components. There are a variety of products available, and not all deliver nicotine.

Generally, a battery-powered heating coil heats the liquid contained in a cartridge to form the vapour, which is then inhaled by the user. The vapour is mainly made up of water, propylene glycol and glycerine, with low levels of other chemicals also present. Unlike chewing gum and patches, e-cigarettes mimic the experience of cigarette smoking because they are hand-held and generate a smoke-like vapour when used. They can provide smokers with a nicotine ‘hit’ and help to recreate similar sensations of smoking without exposing them or others to the smoke from conventional cigarettes. They are used by many smokers but little has been known about how effective they are at helping people to stop, nor their long term effects.

Modern e-cigarettes were first designed and produced in China in 2003 and were marketed in 2004, being exported internationally shortly after. The industry has grown to be worth around US$3 billion and made up of 466 manufacturers worldwide.

More than 50 per cent of current smokers report ever having tried e-cigarettes, up from 8.2 per cent in 2010, with a similar increase in current smokers reporting regular use of e-cigarettes (2.7 per cent in 2010 compared with 17.6 per cent in 2014). Because e-cigarettes are a relatively new technology, there is debate over the potential drawbacks (attracting non-smokers to smoking and posing a danger to smokers who make the switch to e-cigarettes) and benefits (helping smokers avoid smoking-related disease) of e-cigarettes.

Effects on non-smokers

There are as yet no data to support the fear that e-cigarettes may act as a gateway to smoking conventional cigarettes among those who have never smoked.

According to UK public health body Action on Smoking and Health, the number of never-smokers who report having tried e-cigarettes has increased from 0.5 per cent in 2012 to 1.1 per cent in 2014, and those reporting regular use has remained very low (0.1 per cent in 2012 and 0.2 per cent in 2014). During the time in which e-cigarettes became popular in England, the national prevalence of smoking tobacco cigarettes and using any nicotine product have both continued to decline.

Review method

The team of researchers from the UK and New Zealand found two randomised trials that had analysed data from 662 current smokers.

The researchers looked at the effects of electronic cigarettes on quit rates and the number of people who were able to reduce the number of cigarettes they smoked by at least 50 per cent. They also looked at any adverse effects reported by electronic cigarette users. The team also considered evidence from 11 observational studies.

Results show benefits, but limited by small number of studies

The researchers said the results showed beneficial effects of e-cigarettes, but were limited by the small number of trials and limited sample of people who were analysed in the studies.

About 9 per cent of smokers who used electronic cigarettes were able to stop smoking at up to one year. This compared with around 4 per cent of smokers who used the nicotine-free electronic cigarettes.

When the researchers looked at the data on reducing cigarettes in people who had not quit, they found that 36 per cent of electronic cigarette users halved the number of conventional cigarettes. This compared with 28 per cent of users who were given the placebos. Only one of the trials looked at the effects of electronic cigarettes compared with patches and this study suggested similar efficacy of the two treatments. No serious adverse effects occurred over short to mid-term electronic cigarette use.

In May 2014, Australian Food News reported that a study from the University College London found that people attempting to quit smoking without professional help were approximately 60 per cent more likely to report succeeding if they used e-cigarettes than if they used willpower alone or over-the-counter nicotine replacement therapies such as patches or gum.

“Although our confidence in the effects of electronic cigarettes as smoking cessation interventions is limited because of the small number of trials, the results are encouraging,” said Peter Hajek, the review’s co-author, and Professor of Clinical Psychology.

“Both trials used electronic cigarettes with low nicotine delivery and it is likely that more recent products are more effective as previous research suggests that higher and faster nicotine delivery facilitates treatment effects,” Professor Hajek said. “Several ongoing studies will help to answer the question more fully,” he said.

No evidence of health risk for e-cigarettes

Another of the review’s co-authors, Jamie Hartmann-Boyce, said e-cigarettes had become popular with smokers who wanted to reduce the risk of smoking.

Ms Hartmann-Boyce said none of the studies in this review found that smokers who used electronic cigarettes short-term (2 years or less) had an increased health risk compared to smokers who did not use electronic cigarettes.

“We did not find any evidence from observational studies that people who used electronic cigarettes at the same time as using regular cigarettes were less likely to quit smoking,” Ms Hartmann-Boyce said. “Findings suggest electronic cigarettes with nicotine help people stop or reduce smoking when compared to electronic cigarettes without nicotine, but more studies are needed,” she said.

Health experts welcome review

Professor Ann McNeill, Professor of Tobacco Addiction, National Addiction Centre, King’s College London’s Institute of Psychiatry, welcomed the new Cochrane review, saying that while the studies included in the review were limited in number and used e-cigarettes which are now largely obsolete, the results were “clear”.

“E-cigarettes are helping smokers to quit or substantially cut down the number of cigarettes they smoke,” Professor McNeill said. “I hope now the debate can move on to how best we can advise and support smokers using these products to stop smoking completely as soon as possible,” she said.

The review was also welcomed by Professor Robert West, Editor-in-Chief of Addiction and Director of Tobacco Research at UCL.

“This study tells us that even the older style electronic cigarettes improve smokers’ chances of stopping by about 50 per cent,” Professor West said. “It’s early days but so far it seems that these devices are already helping tens of thousands of smokers to stop each year,” he said.

Not all health experts convinced about e-cigarettes safety

However, not all health experts are convinced about the safety of e-cigarettes. In a commentary published recently in the open access journal BMC Medicine, Charlotta Pisinger, Associate Professor and Senior Researcher at the Research Centre for Prevention and Health, Glostrup Hospital, Denmark, said that “everything seems harmless” when compared with a conventional cigarette.

“For a smoker reluctant to stop smoking the e-cigarettes will most probably be a less harmful alternative – but we cannot focus on these smokers only,” Associate Professor Pisinger said. “The potential health benefits obtained by some smokers must out-weigh the potential harm by use of ex- and never-smokers, of smokers who intended to quit but switched to e-cigarettes, of smokers’ dual use and of eventual re-normalization of smoking,” she said.

“Most probably e-cigarettes are less harmful than conventional cigarettes, but they can hardly be called safe,” Associate Professor Pisinger said. “Consequences of e-cigarettes use must be viewed in a long-term public health perspective, including both smokers and non-smokers,” she said.

In another recent article published in food law journal FoodLegal Bulletin, FoodLegal Food Chemist, Tony Zipper examined a recent article published by the Journal of the American Medical Association, which reported the results of a literature review which held certain chemicals to pose a public health risk when inhaled.

Many of these same chemicals are permitted to be added to food or oral ingestion without much regulation. However, Mr Zipper illustrated in his article that there were considerable opportunities for food chemicals to be absorbed into the human body by means other than ingestion. Mr Zipper’s article queried whether ingestion should be the only accepted means of food intake when food regulators prescribe acceptable levels of food chemicals.

E-cigarettes increased popularity

Electronic cigarettes have been around in some form for a number of years but recently their popularity has increased substantially. In April 2014, Australian Food News reported that while sales of smoking cessation aids had slowed in the UK, the market for e-cigarettes grew from an estimated million in 2012 to reach an estimated £193 million in 2013.

Regulation

The EU Tobacco Products Directive, which must be transposed by member states into national law by May 2016, regulates e-cigarettes containing up to 20mg/ml nicotine including their size, safety and quality, as well as advertising and consumer warnings.

Advertising of e-cigarettes is allowed in the UK, but adverts must not be directed towards under-18s, nor encourage non-smokers to use e-cigarettes. Despite the World Health Organization recommendations, the use of e-cigarettes in public places is not regulated nationally, though bans are in in place in some establishments.

Meanwhile, in Australia no e-cigarette products have been approved as yet for sale or use by the Therapeutic Goods Administration (TGA) in Australia.