Nearly 30,000 people tested quit-smoking methods. One stood out

Smoking remains the world's leading cause of preventable disease and death. According to the World Health Organization (WHO), it is responsible for more than seven million deaths each year, including 1.6 million deaths among non-smokers exposed to second-hand smoke.

The findings come from a living systematic review, meaning researchers continually update the analysis as new evidence becomes available. The latest version included 80 randomized controlled trials involving 29,861 participants, with nine new trials added in this update.

Nicotine Vapes Outperform Patches and Gum

The researchers found high-certainty evidence that nicotine e-cigarettes produced higher quit rates than nicotine replacement therapy (NRT), such as patches and gum. For every 100 people, nicotine e-cigarettes resulted in about 4 additional people successfully quitting.

Nicotine e-cigarettes also performed better than non-nicotine cigarettes, leading to about 2 additional quitters per 100 people.

People given e-cigarettes also had higher quit rates than those who received no support or behavioral support (such as individual counseling and group programs). However, the researchers had less confidence in this comparison because of potential bias in how some of the studies were designed.

"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 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 9 new trials and our main conclusions haven't changed."

What the Evidence Says About Vaping Risks

Researchers found no evidence that using e-cigarettes to quit smoking increased the risk of serious harm, although they emphasize that longer-term research is still needed.

The conclusions apply specifically to regulated, nicotine-containing e-cigarettes. Illicit products and e-cigarettes containing other substances, such as THC, may present 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."

Major health organizations and agencies, including the WHO, continue to warn that e-cigarettes expose users to nicotine and other chemicals that can be harmful. Health officials have also raised concerns that e-cigarette use among children and young people can lead to nicotine addiction and later use of tobacco products.

A Step Away From Cigarettes, Not a Risk-Free Endpoint

The researchers stress that e-cigarettes may not be the best quitting method for everyone. People who want to stop smoking are encouraged to speak with stop-smoking support services or their clinicians about the most appropriate approach.

Vaping still carries health risks. However, the authors say those risks are much smaller than the dangers associated with continuing to smoke cigarettes.

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 views switching to e-cigarettes as a possible stage in the process of moving away from smoking, rather than necessarily the final destination.

"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."