New research has found that people are just as likely to transition from vaping to smoking as smoking to vaping.

The University of Otago study, published on Wednesday in journal Drug and Alcohol Review, analysed data related to New Zealanders' smoking and vaping status from the 2018-2020 New Zealand Attitudes and Values survey.

Post-graduate student Andre Mason said in 2018, those who vaped were more likely to start smoking than those who smoked were to start vaping, while in 2019, the opposite effect was found.

"We found that there was an equal likelihood of vapers transitioning to smoking as smokers were to vapers."

Mason said there was not enough information to say whether vaping was a gateway to smoking, but it showed that people were transitioning between them.

"It means that the issue, when we're considering vaping-related policy, is more complex than simply saying that it works to stop smokers - because it could also be contributing to an uptake in smoking as well."

Recent estimates suggested New Zealand had the second-highest rates of ever using (15.5 percent) or currently using (7.8 percent) nicotine vaping products in the world.

Unlike other studies, Mason and associate professor Damian Scarf found no consistent evidence that vaping acted as a cessation pathway from smoking.

Mason said vaping appeared to be another smoking-related behaviour, rather than a substitute for smoking that primarily helped people quit.

"Furthermore, and perhaps more concerning, vaping appeared to be equally as likely to increase the uptake of cigarette smoking as it was to have a cessation effect."

Although the prevalence of smoking decreased over time, the lack of evidence for a cessation effect through vaping suggested the drop may be due to other factors, such as marketing campaigns focused on the negative health impacts and increased costs of buying cigarettes.

Quit vaping research grant

The government has given $1.4 million to a large trial to help New Zealanders quit vaping.

Over six months, more than 1000 participants will test whether cytisine - a medicine that partially blocks the effects of nicotine on the brain - is more effective than a tapered reduction in nicotine, when accompanied with text behavioural support from Quitline.

Anyone 16 and over who has used nicotine vapes daily for six months will be eligible.

University of Auckland associate professor Natalie Walker said it was the first trial of its kind in New Zealand.

"Many of the clinical trials are done in the USA and tend to look only at people under 30. They often don't include people who have never smoked, so this study will be different because we're going to be able to look at people who have never smoked, as well as those that have smoked and vape.

"Over time, people who vape may also wish to stop, yet little evidence exists on the best ways to support people to do this.

"Our trial will also assess whether interventions for quitting vaping have any unintended consequences on smoking rates."

Recruitment for the trial will begin in January 2024.