Autores: Constanza P Silva, PhD, Jennifer L Maggs, PhD, Brian C Kelly, PhD, Mike Vuolo, PhD, Jeremy Staff, PhD
Abstract
Introduction
Nicotine exposure via early combustible cigarette smoking can prime the adolescent brain for subsequent cocaine use. However, there is limited evidence whether e-cigarette use, a nicotine delivery system that is increasingly popular among youth, is associated with later cocaine use. We examine the association between e-cigarette use by age 14 and cocaine use by age 17.
Methods
The Millennium Cohort Study (MCS) is a nationally representative sample of 18,552 9-month-old children born between September 2000 and January 2002 in the United Kingdom. Follow-up interviews and surveys were collected from children and their caregivers at modal ages 3, 5, 7, 9, 11, 14, and 17. Our analytic sample included 340 youth who had used e-cigarettes by age 14 (exposure variable), matched using coarsened exact matching (CEM), to 5,568 nicotine-naïve youth on childhood common liability confounders and demographics measured from infancy to age 11. The outcome was cocaine use by modal age 17.
Results
Of the 5,207 successfully matched youth, 7.6% of adolescent e-cigarette users by age 14 used cocaine by age 17 versus 3.1% of non-e-cigarette users. Multivariable logistic regression in the matched sample indicated that e-cigarette use by age 14 was associated with 2.7 times higher odds of cocaine use by age 17 (95% CI, 1.75-4.28).
Conclusions
These findings in a UK sample showed that e-cigarette use in early adolescence is associated with higher odds of cocaine use later in adolescence, similar to risks posed by tobacco cigarette smoking.
Implications
In this large-scale prospective cohort study (n=5,207), youth who had used e-cigarettes by age 14 were matched to nicotine naïve youth on childhood common liability confounders and demographics measured from infancy to age 11 (e.g., school engagement, thrill-seeking behavior, delinquency, peer and parental smoking, parental educational attainment). After matching, 7.6% of age 14 e-cigarette users had subsequently used cocaine by age 17 versus 3.1% of non-e-cigarette users. Although e-cigarettes are promoted as a strategy for nicotine-dependent users to reduce harms of combustible cigarettes, evidence here suggests that for nicotine-naïve youth, they may increase the risk of subsequent cocaine use.
