A survey of New Zealand vapers has found most people started smoking e-cigarettes to quit smoking - and for the majority, it worked.
The online survey, led by Dr Penny Truman from Massey University in 2016, recruited 218 people through vaping and smoking-cessation networks.
Almost all had been smokers, but three quarters no longer smoked, and the remainder significantly reduced their tobacco use. Three had not been smokers before they started vaping, but had not gone on to smoke tobacco.
Most vapers surveyed also waited longer in the morning before vaping than they had when smoking, and generally reduced nicotine levels in their e-cigarette liquid over time.
The results suggest some people switch from smoking to vaping quickly and completely, but others have a longer transition, Truman said.
"Most of the participants had changed the type of vaporiser they used several times. There was also a pattern of moving away from tobacco flavoured e-liquids, experimenting with many different flavours until they found several they liked and then continued to use on an ongoing basis."
Selling and supplying e-liquids containing nicotine is illegal in New Zealand, but the Government is planning to legalise them and many shops already sell them over the counter.
The researchers, who included Massey public health Professor Marewa Glover and former director of Action on Smoking and Health (Ash) Trish Fraser, concluded legalising such products would remove a main barrier for smokers who want to switch to vaping.
They called for more randomised studies, including research following new vapers who are attempting to quit smoking. There are around 63,000 daily vapers in New Zealand and an unknown number who vape less regularly.
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Most international research has found e-cigarettes are harmful, but they are less so than tobacco.
Glover said changing the law and setting minimum quality standards could help speed the transition from smoking to vaping.
"It would also provide clarity around the greatly reduced risk associated with vaping compared to smoking, which would encourage more people to make the switch."
Glover has come out in support of e-cigarettes in the past, calling for an incentive programme to help smokers make the switch.
She said "innacurate information" about vaping was being spread by and among health professionals.
"This needs to stop because it is keeping people smoking – the very opposite of what we want if we are serious about reaching the smoke-free goal of five per cent or less smoking by 2025."
The study was funded by the Tobacco Control Research Tūranga programme, set up by the Ministry of Health and the Health Research Council of New Zealand.