Exploring the Bi-Directional Association between Tobacco and E-Cigarette Use among Youth in Canada.

Introduction:
This article explores the bi-directional association between tobacco use and e-cigarette use in a large longitudinal sample of Canadian youth. The study aims to determine whether reciprocal relationships exist between e-cigarette and tobacco use among Canadian adolescents.

Key Points:

* The study used a longitudinal sample of secondary students (n =6729) attending 87 schools in Ontario and Alberta, Canada, who completed the COMPASS student questionnaire across three waves (from 2014–2015 to 2016–2017).
* The study found that current e-cigarette use predicted subsequent tobacco use between Wave 1 (W 1) and Wave 2 (W 2) of the study (W1–2: OR =1.54, 95% CI =1.37--1.74).
* The study also found that current tobacco use predicted e-cigarette use during earlier waves of the study (W 1--2: OR =1.43, 95% CI =1.30--1.58).
* However, these relationships dissipated in later waves, when tobacco use no longer predicted e-cigarette use (W 2--3: OR =1.07, 95% CI =0.99--1.16).
* The study controlled for relevant covariates such as gender, grade, ethnicity, having friends that smoke, weekly spending money, cannabis use, and binge-drinking behaviors.
* The study adjusted for the nested structure of the data (i.e., students nested within schools).
* The study found that rates of past-month tobacco use and e-cigarette use increased across the three waves examined, demonstrating a rise in the number of students that were using tobacco products and e-cigarettes over time.

Main Message:
The study highlights the complex relationship between e-cigarette use and tobacco use among Canadian youth. It suggests that e-cigarette use may influence and be influenced by tobacco use, and that nicotine delivery system-specific intervention efforts targeting both tobacco use and e-cigarette use may be warranted. The study also emphasizes the need for policies that discourage youth from using e-cigarettes, particularly nicotine-containing e-cigarettes, as nicotine has been seen to affect the developing adolescent brain. Furthermore, regulations such as ad placement restrictions may act as a potential strategy to limit youth exposure to e-cigarette advertisements.

Aleyan S, Gohari MR, Cole AG, Leatherdale ST. Exploring the Bi-Directional Association between Tobacco and E-Cigarette Use among Youth in Canada. International journal of environmental research and public health. 2019;16(21). doi:10.3390/ijerph16214256