By Linda Carroll

(Reuters Health) – Among teens, using e-cigarettes may raise the risk of progressing to cigarette smoking, a new U.S. study suggests.

Overall, adolescents who used e-cigarettes before trying any other tobacco products were more than four times as likely to be smoking traditional cigarettes within a couple of years compared to those who had never tried any type of vaping device or non-cigarette tobacco products, the study team reports in JAMA Network Open.

“E-cigarettes may be a pathway to cigarette smoking, and a sizeable one,” said senior study author Andrew Stokes of the Boston University School of Public Health.

Overall, smoking rates have dropped significantly, Stokes said. “That’s been a real success story for public health and in that context, it’s pretty alarming that a new product has come on the market potentially drawing a whole generation into using tobacco,” he added.

Stokes and his colleagues explored the influence of e-cigarettes through the Population Assessment of Tobacco and Health Study (PATH), a nationally-representative sample of kids aged 12 to 15 who completed annual questionnaires between 2013 and 2016.

Along with questions about vaping and smoking, the surveys asked about kids’ socioeconomic backgrounds and their attitudes about smoking. They were also asked questions designed to illuminate how prone they were toward risky behaviors and sensation-seeking.

Those who reported using a tobacco product in the three years of surveys were asked which of 12 products they had “tried first,” including traditional cigarettes, cigars, pipes, hookahs, chewing tobacco, snus and e-cigarettes.

Stokes and his colleagues focused on the 6,123 kids who said in the first-wave survey that they had never used any tobacco product. By the third survey, 6.1 percent of these kids reported smoking or having tried traditional cigarettes.

Among kids who had first tried e-cigarettes, just over 20 percent had tried or were regularly smoking cigarettes by wave three, and among kids who first tried other non-cigarette tobacco products, more than 21 percent had tried or were smoking cigarettes. That compares with just 4 percent of kids who had not used any type of non-cigarette tobacco products.

Researchers calculated that the odds of trying traditional cigarettes or becoming regular smokers were 4.09 times higher for those who tried e-cigarettes first, and 3.84 times higher after trying other non-cigarette tobacco products first.

But for those kids considered to be at low risk for taking up smoking – who had initially said they had no interest in smoking, were risk averse and less likely to seek out new experiences – first using e-cigarettes raised the risk of eventual smoking by 8.57 times. This added risk wasn’t seen among first users of other non-cigarette products.

Stokes suspects that there are several reasons why kids who don’t see themselves ever smoking cigarettes might be open to vaping. First, he said, many don’t realize that nicotine is a highly addictive substance. “And there is also the ‘cool factor,'” he said. “The flavors are very appealing and we know that they are disproportionately appealing to youth, who are exposed to a lot of marketing targeted to them on social media.”

The new findings are “pretty consistent with what we’ve seen before in this area in terms of demonstrating that people who experiment with electronic cigarettes, even if they swear at baseline that they would never smoke regular cigarettes, are at much more risk of transitioning to regular cigarettes,” said Dr. Brian Primack, director of the Center for Research on Media, Technology and Health at the University of Pittsburgh in Pennsylvania.

The new study “strengthens earlier findings in a couple of ways,” Primack said. “First, this is a very large and prestigious database and that is important with an area as controversial as this. You want to make sure your evidence is as strong as possible. The other thing it does is show that the magnitude of risk is even higher for those at low risk for using cigarettes. We’ve been seeing hints of this all along. And this is particularly problematic for people who probably would never have touched a cigarette to begin with.”

SOURCE: JAMA Network Open, online February 1, 2019.