People who use e-cigarettes are three times more likely than people who don’t vape to take up regular cigarettes, according to a review of 25 studies.

The researchers from Australian National University said their review was the first to examine links between e-cigarette use and regular cigarette use across the whole population, including youth, adults and former smokers, The Guardian reports.

Lead researcher Emily Banks said all of the 25 studies examined by her team found people who used e-cigarettes were more likely to start smoking regular cigarettes compared with those who had not used tobacco or e-cigarettes. She noted there is limited evidence that e-cigarettes help people quit smoking.

“Our review found that there wasn’t sufficient evidence to conclude that e-cigarettes are effective for quitting smoking compared to other approaches, but there are promising signs that they have potential to help,” she said in a news release. “The evidence also indicates that e-cigarettes tend to lead to prolonged use of nicotine, rather than quitting the habit entirely.”