Employing the theory of planned behaviour to design an e-cigarette education resource for use in secondary schools

Background: An extended version of the theory of planned behaviour (TPB) was used to inform the design of a framework for an educational resource around e-cigarette use in young people. Methods: A sequential exploratory design was employed. In Phase 1, elicited behavioural, normative and control beliefs, via 7 focus groups with 51 participants, aged 11–16 years, identified salient beliefs around e-cigarette use. These were used to construct a questionnaire administered to 1511 young people aged 11–16 years, which determined predictors of e-cigarette use and ever use. In Phase 2, sociodemographic variables, e-cigarette knowledge, access, use, marketing and purchasing of e-cigarettes and smoking behaviour were also gathered. The composite findings from Phase 1 and 2 informed the design of a post primary educational resource in Phase 3 around e-cigarette use. Results: Current e-cigarette use was 4%, with almost 23% reporting ever use, suggesting current use is stable but experimentation may be increasing in this cohort. Sociodemographic variables, knowledge of e-cigarettes, smoking behaviour and TPB variables (direct and indirect measures of attitudes, subjective norm, and perceived behavioural control) accounted for 17% of the variance in current e-cigarette use, with higher intentions to use e-cigarettes within the next month, having the strongest impact on use (p < 0.001), followed by self-efficacy (p = 0.016). Sociodemographic and TPB variables accounted for 65% of the variance in intentions to use e-cigarettes in the next month; current e-cigarette use (p < 0.001), more positive attitudes (p < 0.001), stronger social influence (p < 0.001), higher self-efficacy (p < 0.001), higher control beliefs (p < 0.001) and greater motivation to use e-cigarettes (p < 0.001) were the main predictors of intentions. Phases 1 and 2 informed the mapping of key predictors of intentions and use of e-cigarettes onto the Theoretical Domains Framework, which identified appropriate intervention functions and behaviour change techniques. Conclusions: This paper is the first to bridge the theoretical-practice gap in an area of significant public health importance through the development of a framework for a novel theory driven school-based educational resource aimed at reducing experimentation and uptake of e-cigarette use in young people.