The use of e-cigarettes produced up to 22K additional long-term quitters in England in 2014, according to latest estimates.

The research team from University College London defined a long-term quitter as someone who has not smoked for at least one-year.

Writing in their paper published in Addiction the research team led by Professor Robert West said an important consideration when assessing the public health impact of e-cigarettes was how far they contribute to, or detract from, smoking cessation in the population.

There had been speculation from certain public health experts that e-cigarettes undermined quitting and could act as a gateway to smoking cigarettes.

A recent review published in the  Lancet Respiratory Medicine that suggested those who use e-cigarettes are less likely to quit than smokers (read our story here).

Read our analysis: The vape debate: smoker’s salvation or gateway drug?

But without engaging appropriately with the relevant data these assertions are based on unreliable assumptions, they said.

Using figures from monthly national surveys the researchers estimated that 2.5% of the smokers who used an e-cigarette in their quit attempt in England (22K people) succeeded who would have failed if they had used nothing or bought a licensed nicotine product from a shop.

However e-cigarettes could have detracted people from using other methods of stopping that are equally or more effective, the authors said.

If this were the case then adjusting the figures would mean the number of people helped by e-cigarettes would be lower at 16K.

Professor Robert West, who led the research team, said “E-cigarettes appear to be helping a significant number of smokers to stop who would not have done otherwise – not as many as some e-cigarette enthusiasts claim, but a substantial number nonetheless.”

“There have been claims by some public health researchers that e-cigarettes undermine quitting if smokers use them just to cut down, and that they act as a gateway into smoking.

“These claims stem from a misunderstanding of what the evidence can tell us at this stage, but this is clearly something we need to watch carefully,” he added.