A study of more than 10,000 young people found that e-cigarettes act as a gateway to the real thing, making those that use them 2.5 times more likely to start smoking cigarettes. The e-liquid in e-cigarettes contains nicotine, and some teenagers showed signs of addiction within one months of starting to use the devices.
Cigarettes have fallen relatively out of favor with teenagers, but this research follows recent National Institute of Drug Abuse findings that vaping is increasingly popular with the age group, many of whom are not sure what exactly they are smoking.
The study authors found that all cigarette alternatives raised the odds that the teenagers would later try cigarettes too, suggesting that changes to policy are needed to discourage young people from taking up any for of smoking. Other alternatives, including hookahs, non-cigarette combustible tobacco such as cigarillos or smokeless tobacco, trigger conventional smoking just as quickly.
The study of teenagers is the first time scientists have compared the trendy products simultaneously with subsequent cigarette use, and follows other recent research that has shown the direct health risks of e-cigarettes.
Studying the effect of e-cigarettes on the behavior of teenagers is crucial because, as the study points out, 90 percent of adults who smoke tried their first cigarette before they were 18.
At the outset of teen the study, none of the 12- to 17-year-old male and female participants had smoked a cigarette. The researchers followed up with them 12 months later.
Study author and University of California, San Francisco dentistry professor Dr Benjamin Chaffee said: 'We estimated that 'ever use' of e-cigarettes was associated with 2.53 times greater odds of subsequent cigarette use.'
He added: 'Among youths who had never smoked a cigarette at baseline, adjusted odds of any cigarette use initiation were approximately double for ever users of e-cigarettes, hookah, non-cigarette combustible tobacco and smokeless tobacco compared with never users.
'Odds of past 30-day cigarette use at follow-up were also approximately double for ever users of e-cigarettes, hookah, non-cigarette combustible tobacco and smokeless tobacco compared with never users.'
Dr Chaffee, of the Center for Tobacco Control Research and Education at the University of California, San Francisco, added that the use of more than one product increased the risk even more.
He said non-cigarette tobacco use among teenagers increased between 2011 and 2015, as e-cigarettes and hookahs became increasingly popular.