Trends and predictors of exclusive e-cigarette use, exclusive smoking and dual use among youth in Canada

Abstract

Background: Few studies have examined predictors of exclusive e-cigarette use, exclusive smoking and dual use among youth. We investigated whether frequency of e-cigarette use and cigarette smoking predicted involvement in different usage groups after a 1- and 2-year follow-up among a sample of Canadian youth.

Methods: A longitudinal sample of youth who participated in three waves of COMPASS [Wave 1 (W₁) 2015/16, Wave 2 (W₂) 2016-17, Wave 3 (W₃) 2017/18] was identified (N = 5,704). Multinomial logistic regression was used to examine whether frequency of e-cigarette use and cigarette smoking at W₁ predicted involvement in different usage groups at W₂ and W₃. Similarly, we examined whether changes in frequency of e-cigarette use and cigarette smoking between W₁ and W₂ predicted involvement in different usage groups at W₃.

Results: E-cigarette users reporting use on 4 or more days per month at W₁ had greater odds of dual use at W₂, compared to non-users (aOR = 11.22, p < 0.0001). Those who reduced their frequency of e-cigarette use between W₁ and W₂ had lower odds of exclusive e-cigarette use and dual use at W₃ (aOR = 0.18 and 0.17 respectively; both p < 0.05). Those who increased their frequency of cigarette smoking between W₁ and W₂ had higher odds of exclusive smoking and dual use at W₃ (aOR = 22.65 and aOR = 9.92 respectively; both p < 0.0001).

Discussion: Reductions in frequency of e-cigarette use appeared to have a protective effect of reducing exclusive e-cigarette use and dual use at follow-up. Increases in frequency of cigarette smoking were a significant predictor of exclusive smoking and dual use.

Keywords: Cigarettes; Dual use; E-cigarettes; Predictors; Smoking; Youth.