Over 29 million people in the European Union (EU) have tried electronic cigarettes, despite the fact that the jury is still out on whether they actually help people to quit smoking, a new study has found.

This marks the largest study to date on the use of e-cigarettes in the EU. It involved over 26,000 people from 27 countries.

It found that 20% of current smokers have tried e-cigarettes at least once, along with 4% of ex-smokers and 1% of people who have never smoked. Using this data, the researchers estimated that more than 29 million adults in the EU had tried them.

They expressed their surprise at these figures given that the study was based on data from 2012, which was before the e-cigarette industry really took off.

E-cigarettes are battery-powered devices designed to supply nicotine through inhaled water vapour. They are currently at the centre of a major debate, with some people stating that they can help smokers to quit the habit and others insisting that they are potentially harmful to health.

As a result of potential health concerns, the HSE introduced a ban on e-cigarettes in all hospitals and health facilities from May 1. It said this ban 'followed a detailed review of their safety' and insisted that ‘there currently is no conclusive evidence that e-cigarettes are safe for long-term use, or are effective as a smoking cessation aid'.

However last month, over 50 respected doctors and professors from around the world wrote a letter to the World Health Organization stating that tobacco harm reduction products, including e-cigarettes, ‘could be among the most significant health innovations of the 21st century', with the potential to save millions of lives.

This latest study found that among smokers, the use of e-cigarettes was more likely among 15-year-olds than older smokers. It was also more likely among heavy smokers (six or more cigarettes per day) than light smokers (five or less per day).

The findings also suggested that smokers are using e-cigarettes as smoking cessation devices, as those who had tried to quit the habit in the last 12 months were twice as likely to have used them compared to those who had never tried to quit the habit.

"As e-cigarettes represent an emerging market in which the tobacco industry has extensively invested, it is imperative to identify the population subgroups that are more likely to use them and the subsequent implications this might have on public health

"These new findings show that millions - including many young people and smokers trying to quit - are trying e-cigarettes, which underscores the importance of assessing their potential harm or benefits," the researchers from the Harvard School of Public Health in the US said.

They noted that the findings emphasise the ‘miracle versus menace' discussion surrounding e-cigarettes. On the one hand, they may reduce tobacco use, but on the other hand, they may renormalise smoking and maintain nicotine addiction.

They called for more research in this area.

Details of these findings are published in the journal, Tobacco Control.