Using e-Cigarettes makes Young Adults more than four times more likely to transition to traditional cigarettes within 18 months, according to new University of Pittsburgh research, suggesting that e-cigarettes may be serving as a gateway to traditional tobacco cigarettes for young people with no prior history of smoking.

Writing in the American Journal of Medicine, lead author Brian A Primack and colleagues explain that although e-cigarettes may help some smokers kick the habit, some young adults that have never smoked before are taking up recreational e-cigarette use in large numbers.

They argue there could be a link between e-cigarette use and later progression to smoking tobacco cigarettes, especially in this group of young non-smokers.

The study team used a group of 1,506 randomly-selected adults aged 18 to 30, who completed a questionnaire about their tobacco use. Eighteen months later, 915 of those that had never smoked cigarettes completed a second survey. The responses were then weighted to make the overall data representative of the US population.

Eleven percent of the responders started smoking tobacco in the 18 months between the two surveys. This was far more common in those who had been using e-cigarettes, 47.7 percent of whom graduated to traditional tobacco cigarettes in this time.

Only 10.2 percent of those who did not use e-cigarettes had moved on to tobacco within this 18-month period.

A help or a hindrance?

A British study published by the British Medical Journal including over 160,000 subjects indicated that e-cigarette usage can be a valuable tool to help people stop smoking. In this study, 8 percent of those using e-cigarettes were able to quit for at least three months, compared to 5% of those who did not use e-cigarettes.

Another recent study found that e-cigarette use can help improve the long-term health of users compared with tobacco use, showing a 96% reduction in adverse health problems by users of three or more years.

However, scientists are still a long way from fully understanding the effects of this technology, while the e-cigarette industry - increasingly dominated by big tobacco companies who have identified the technology as a new and less controversial revenue stream - continues to grow.

A growing market

The popularity of e-cigarettes has grown significantly since their introduction to the global market in 2004, spurred by the decreasing popularity of tobacco cigarettes. Initially seen as somewhat of a novelty product, they have now become a common sight. Despite this growth in use, a study published earlier this year suggests that traditional cigarettes continued to outsell e-cigarettes by a ratio of 64:1 in the USA from 2011 to 2015.

According to the US Centers for Disease Control and Prevention, in 2014 there were nine million vapers in the USA, accounting for 43.2 percent of the world's e-cigarette users.