Youth vaping and smoking and parental vaping: a cross-sectional survey
While results for youth vaping and youth smoking associations indicated support for underlying propensities, estimated effects still required considerable unmeasured confounding to be explained fully, and indicated that if youth vaping does increase risk of youth smoking, this effect may be stronger in the general population of youth, than among those youth who typically vape.
Abstract
Background: Concerns remain about potential negative impacts of e-cigarettes including possibilities that: youth e-cigarette use (vaping) increases risk of youth smoking; and vaping by parents may have impacts on their children’s vaping and smoking behaviour. Methods: With cross-sectional data from 3291 youth aged 10-15 years from the Understanding Society Survey, we estimated effects of youth vaping on youth smoking (ever, current and initiation in the past year), and of parental vaping on youth smoking and vaping, and examined whether the latter differed by parental smoking status. Propensity weighting was used to adjust for measured confounders and estimate effects of vaping under alternative scenarios of no vaping vs universal adoption, and vs observed vaping levels. E-values were calculated to assess the strength of unmeasured confounding influences needed to negate our estimates. Results: Associations between youth vaping and youth smoking were attenuated considerably by adjustment for measured confounders. Estimated effects of youth vaping on youth smoking were stronger comparing no use to universal adoption (e.g. OR for smoking initiation: 32.5; 95% CI: 9.8-107.1) than to observed levels of youth vaping (OR: 4.4; 0.6-30.9). Relatively strong unmeasured confounding would be needed to explain these effects. Associations between parental vaping and youth vaping were explained by measured confounders. However, estimates for parental vaping on youth smoking indicated effects, especially for youth with ex-smoking parents (e.g. OR for smoking initiation: 11.3; 2.7-46.4) rather than youth with currently smoking parents (OR: 1.0; 0.2-6.4). Relatively weak unmeasured confounding could explain these parental vaping effects. Conclusions: While results for youth vaping and youth smoking associations indicated support for underlying propensities, estimated effects still required considerable unmeasured confounding to be explained fully. However, these estimates from cross-sectional data could also be explained by smoking leading to vaping. Stronger estimates for universal vaping adoption vs observed usage, indicated that if youth vaping does increase risk of youth smoking, this effect may be stronger in the general population of youth, than among those youth who typically vape. Associations of parental vaping with youth smoking and vaping were either explained by measured confounding or could be relatively easily explained by unmeasured confounding.