Nicotine e-cigarettes are more effective in helping people quit smoking than many conventional methods such as nicotine gums and patches and quitting with behavioural support or no support at all, an updated Cochrane review finds.
Smoking is the leading cause of preventable disease and death, resulting in more than seven million deaths per year, including 1.6 million non-smokers who are exposed to second-hand smoke, according to the World Health Organization (WHO).
The analysis, part of an ongoing living systematic review that is updated as new evidence becomes available, examined 80 randomized controlled trials involving 29,861 participants, nine of which were new to this update.
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 4 more quitters per 100 people. Nicotine e-cigarettes also outperformed non-nicotine cigarettes, resulting in about 2 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 e-cigarettes, though this evidence is less certain due to risk of bias in the study design.
"We have very strong evidence that regulated nicotine e-cigarettes are substantially less harmful than smoking," says Dr Jamie Hartmann-Boyce, senior author of the review from 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 9 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 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," says 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 FDA in the US and MHRA in the UK."
Many major health organizations and bodies including the WHO caution that e-cigarettes still expose users to nicotine and other chemicals which can be harmful. There are also concerns that e-cigarette use by children and youth can lead to nicotine addictions and smoking tobacco products.
The authors caution that e-cigarettes aren't 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 Nicola Lindson, lead author of the review based at the University of Oxford, reflects that: "Quitting smoking is hard and a lot of people who smoke will have tried many times to quit smoking 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."
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."
