Predicting smoking cessation and health risk perceptions : exploring the utility of the Liverpool Lung Project risk model

Abstract

The Liverpool Lung Project (LLP) risk model predicts an individual’s five-year absolute lung cancer risk. Smoking cessation has been identified as the most effective strategy for reducing lung cancer incidence, whilst tailored communications have been considered to be one of the most promising approaches to smoking cessation. The primary aim of this PhD project was therefore to examine whether the LLP intervention was associated with smoking cessation success and lung cancer risk perceptions among Stop Smoking Service (SSS) users. The LLP intervention was developed using the LLP risk model and involves calculation and communication of projected lung cancer risk, based on both smoking and non-smoking behaviour. A number of secondary aims pertaining to risk perceptions and smoking cessation are also considered and described in the main body of the thesis. The project adopted a mixed methods approach, integrating both quantitative and qualitative research components. In relation to the quantitative component, two randomised controlled trials were employed to evaluate the LLP intervention effect on smoking cessation success and lung cancer risk perceptions; baseline current smokers (n = 302) and baseline recent former smokers (n = 219) were recruited from a SSS in Liverpool, UK. All participants completed a baseline questionnaire, which considered socio-demographics, smoking behaviour, and lung cancer risk perceptions. Two separate single-blinded randomised controlled designs were implemented for baseline current and recent former smokers, whereby participants allocated to the intervention arm received the LLP intervention (based upon the LLP risk model). Follow-up smoking status and lung cancer risk perceptions were established at six months. Bivariate and multivariate analyses were undertaken to explore the strength of any associations. Qualitative interviews were additionally undertaken with a sub-set of participants derived from the quantitative research component (n = 30). These interviews intended to explore factors implicated in smoking cessation success and smoking-related risk perception, thus complementing the additional findings of the quantitative research component. Interviews were transcribed and analysed using thematic analysis techniques. The analysis of baseline current smokers revealed that the LLP intervention failed to predict follow-up smoking status or lung cancer risk perceptions; however, the LLP intervention was found to predict follow-up smoking status among baseline former smokers (OR 1.91, 95% CI 1.03-3.55), but not lung cancer risk perceptions. This suggests that those who received the intervention were more likely to be classified as former smokers at follow-up. The qualitative results also provided insight regarding smoking-related risk perception and communication; issues such as perceived lack of control, risk contextualisation, and poor health literacy, were identified to be relevant components to smoking-related risk perception and communication. The results suggest that the intervention may predict follow-up smoking status among recent former smokers, although the trials entailed insufficient statistical power and therefore, an extension of recruitment or implementation of a larger trial is now required to build upon the results. Nevertheless, the current results contribute towards tobacco control research, practice and policy in various ways. For example, the delivery of the LLP intervention among recent former smokers in SSS, and potentially other healthcare settings, could improve smoking cessation rates and would require little time and financial resources. In turn, improved smoking cessation success rates would lead to reduced smoking-related disease and associated deaths.