E-cigarette use is rapidly growing in popularity among youth, and previous research has suggested that youth who use e-cigarettes are more likely to transition to cigarette use.
Less is known about whether e-cigarettes are associated with more frequent cigarette use after initiation, or if adolescents frequently use e-cigarettes as a tool to reduce cigarette use.
In a pooled, retrospective cohort study just published in Pediatrics, researchers analyzed data from three prospective cohort studies in which high school students were surveyed on past-month cigarette and e-cigarette use in 2013-2014 and again in follow-up in 2014-2016.
Compared to students who did not use e-cigarettes, a greater proportion of students who used e-cigarettes at baseline had initiated cigarette use on follow-up, and these students had approximately 4-fold higher odds for initiation of cigarette use after adjusting for sociodemographic factors.
While many baseline, exclusive cigarette users had become non-smokers or exclusive, e-cigarette users at follow-up, the majority remained exclusive cigarette users or endorsed dual product use.
These findings are limited by the length of the study, as more time may be required to observe adolescents to progress to daily smoking. Furthermore, the data may be confounded by unmeasured factors such as behavioral characteristics and peer tobacco use.
Nonetheless, the study is strengthened by its large and geographically diverse sample.
For physicians, these findings suggest that adolescent patients who use e-cigarettes are at greater risk for initiating cigarette use, and that appropriate interventions should be made to reduce this risk.
REFERENCE: Barrington-Trimis et al: E-cigarette Use and Subsequent Smoking Frequency Among Adolescents; http://pediatrics.aappublications.org/content/early/2018/11/01/peds.2018-0486