Gendered associations between e-cigarette use, cigarette smoking, physical activity, and sedentary behaviour in a sample of Canadian adolescents.

Objectives: To examine associations between e-cigarette use, cigarette smoking, physical activity, and sedentary behaviour among a large sample of Canadian adolescents (Grades 9-12) by sex. Methods: Cross-sectional data from 55,629 students who participated in COMPASS Year 6 (2017-2018) were used. Exposures included e-cigarette use and cigarette smoking. Outcomes included meeting recommendations for moderate- to vigorous- physical activity (MVPA;≥60 min/d), muscular strengthening exercises (MSE;≥3 time/wk), and recreational screen time (ST;≤2 h/day) and participating in intramurals or competitive team sports. Logistic regressions were performed after adjusting for relevant covariates. Results: Male adolescents showed higher prevalence of e-cigarette use (40.0% vs 31.3%) and cigarette smoking (4.4% vs 2.9%) than females. Both males and females who used e-cigarettes were more likely to meet MVPA and MSE recommendations, but less likely to meet the ST recommendation than those who did not use e-cigarettes. E-cigarette use was also consistently associated with more sport participation in males, however, among females the results were mixed. Current cigarette use was associated with meeting the MVPA recommendation and less participation in intramurals in males; however, in females, current cigarette smoking was consistently associated with less participation in any sports. Former cigarette use was associated with participation in competitive team sport within school and meeting the MSE recommendation in females only. Conclusions: This study found that associations between e-cigarette use and cigarette smoking with physical activity, sedentary behaviour, and sport participation are largely gendered. Identifying differential co-occurrence of risk behaviours by gender is important for future health promotion efforts targeting physical activity among adolescents.