Nicotine e-cigarettes are more effective in helping people quit smoking than many conventional methods, including nicotine gums and patches and quitting with behavioural support or no support at all, according to an updated Cochrane review led by researchers in the Nuffield Department of Primary Care Health Sciences and published today.
Smoking is the leading cause of preventable disease and death. It results in more than seven million deaths a year, including 1.6 million non-smokers who are exposed to second-hand smoke, according to the World Health Organization (WHO).
The analysis is part of a living systematic review, updated as new evidence becomes available. This update examined 80 randomised controlled trials involving 29,861 participants, nine of which were new.
Vaping 'a proven and viable option'
The review found high-certainty evidence that nicotine e-cigarettes led to higher quit rates than nicotine replacement therapy (NRT), such as patches and gum, resulting in about four more quitters per 100 people. Nicotine e-cigarettes also outperformed non-nicotine e-cigarettes, resulting in about two more quitters per 100.
Compared to no support or behavioural support (such as individual counselling and group programmes), quit rates were still higher when people were also provided with e-cigarettes, though this evidence is less certain because of risk of bias in the study designs.
Dr Nicola Lindson, lead author of the review and Associate Professor in the department's Oxford Tobacco Addiction Group, said: "Quitting smoking is hard and a lot of people who smoke will have tried many times to quit and been unsuccessful. For that reason, it is important that there are a number of different options available to help somebody quit, which could encourage them to keep trying. Although nicotine vapes are unlikely to be completely risk free, they are less harmful than smoking and that is the most important comparison to make for people who are still smoking tobacco."
"We have very strong evidence that regulated nicotine e-cigarettes are substantially less harmful than smoking," said Dr Jamie Hartmann-Boyce, senior author of the review, from the University of Massachusetts Amherst. "Based on the consistency of the findings here, it's clear that they are a proven and viable option for people wishing to quit traditional cigarettes. This update includes nine new trials and our main conclusions haven't changed."
A transition away from traditional cigarettes
The review found no evidence of increased serious harm from using e-cigarettes to quit, though the researchers say longer-term studies are still needed. The findings also apply specifically to regulated, nicotine-containing e-cigarettes; illicit products, or those containing other substances such as THC, may carry different risks.
"It's worth highlighting that our review looks at regulated e-cigarettes containing nicotine, but many of those available on the market do not meet these standards," said Dr Hartmann-Boyce. "Unlicensed e-cigarettes are potentially dangerous, with issues including unstable batteries and harmful chemicals. Anyone looking to use e-cigarettes to quit smoking should only purchase devices that have been tested and approved by their country's regulatory body. Lists of regulated devices are available from the MHRA in the UK and the FDA in the US."
Many major health organisations and bodies, including the WHO, caution that e-cigarettes still expose users to nicotine and other chemicals that can be harmful. There are also concerns that e-cigarette use by children and young people can lead to nicotine addiction and to smoking tobacco products.
The authors caution that e-cigarettes are not necessarily the best way for everyone looking to quit smoking, and that people should contact stop smoking support services or their clinicians for guidance. Vaping also comes with health risks, but, the authors say, those risks pale in comparison to the dangers of smoking.
Dr Hartmann-Boyce sees the switch as a transition rather than an endpoint. "For somebody who is already addicted to nicotine through cigarettes, having a safer alternative like an e-cigarette is something worth considering, especially when other quit aids have proven unsuccessful. We are currently working on a review of interventions to help people quit vaping, which could be the next step along for people looking to transition to a lower-harm product before quitting nicotine altogether."
Read the full review: Electronic cigarettes for smoking cessation, published in the Cochrane Database of Systematic Reviews.
Find out more about the Oxford Tobacco Addiction Group here