31% of teen e-cigarette smokers turned to tobacco within half a year Reuters

Teenagers who use e-cigarettes are more likely to take to tobacco-based products such as cigarettes, cigars and hookah in the future, new research has revealed. US figures for 2014 showed 16% of 10<sup>th graders – aged 15 or 16 – had reported using e-cigarettes in the past 30 days, some 43% of these however had not tried combustible tobacco products.

Adam M Leventhal, of the Keck School of Medicine of the University of Southern California, and colleagues, looked at whether teenagers who reported using an e-cigarette were increasingly likely to take up smoking the following year.

Some 2,530 students across 10 high schools in LA who said they had never tried combustible tobacco participated with 222 e-cigarette users and the rest (2,308) non-users. They found that after six months, 31% of e-cigarette imbibers had tried a combustible tobacco product, compared with just 8% of non-users. After a year, a further 25% of e-cigarette users had tried smoking tobacco, whereas this fell to 9% for non-users.

The authors write in their study published in Jama: "These data provide new evidence that e-cigarette use is prospectively associated with increased risk of combustible tobacco use initiation during early adolescence. Associations were consistent across unadjusted and adjusted models, multiple tobacco product outcomes, and various sensitivity analyses.

"Some teens may be more likely to use e-cigarettes prior to combustible tobacco because of beliefs that e-cigarettes are not harmful or addictive, youth-targeted marketing, availability of e-cigarettes in flavours attractive to youths, and ease of accessing e-cigarettes due to either an absence or inconsistent enforcement of restrictions against sales to minors."