Research has found an association between e-cigarette use in adolescents and the subsequent use of cigarettes, but according to a study published in the July 2016 Pediatrics (published online June 13) adolescents who report e-cigarette use had more than six times the odds of initiating cigarette use in early adulthood than those who had never vaped.

The findings suggest that e-cigarette use may increase the risk of smoking during the transition to adulthood when smoking becomes legal (at age 18). Researchers evaluated 149 e-cigarette users in 11th and 12th grades and matched them with 154 who had never used e-cigarettes, all of whom filled out questionnaires about their nicotine use. Those who reported vaping were 6.17 times more likely to report initiating smoking an average of 16 months later.

Interestingly, stronger associations between vaping at an earlier age and later smoking in participants who reported no intention of smoking suggests that e-cigarette use was not simply a marker for individuals who would have gone on to smoke regardless of e-cigarette use. Researchers concluded that follow-up is required to determine if e-cigarette use among the young—where vaping has become popular—will eventually lead to more established smoking patterns and increases in the diseases associated with smoking.