Assessing the efficacy of behaviourally informed invitation messaging in increasing attendance at the NHS Targeted Lung Health Check: A randomised experimental study

BackgroundLung cancer screening can reduce lung cancer mortality through early detection, but uptake of the NHS Targeted Lung Health Check (TLHC) programme remains low. Behaviourally informed invitation messages have been proposed as a low-cost approach to increase attendance, but evidence of their effectiveness in lung cancer screening is mixed. Few intervention studies used evidence-based behaviour change frameworks, and rarely tailored invitation strategies to empirically identified barriers and enablers. MethodsIn an online experiment, 3,274 adults aged 55-74 years and with a history of smoking were randomised to see one of four behaviourally informed invitation messages or a control message. Participants then rated their intention to attend a TLHC appointment, and selected barriers and enablers to attending from a pre-defined list, which were classified according to the Theoretical Domains Framework. Invitation messages were mapped to Behaviour Change Techniques using the Theory and Techniques Tool. Message conditions were compared on intention to attend TLHC using bootstrapped ANOVA followed by pairwise comparisons. Exploratory counterfactual mediation analyses examined the role of fear in intention to attend. ResultsBehaviourally informed invitation messages did not meaningfully increase intention to attend TLHC compared with the control message. While a GP-endorsed message showed a small potential benefit relative to the other conditions, this finding was not robust after adjustment for multiple comparisons. Participants most frequently reported barriers related to Emotion (particularly fear), Social Influence, and Knowledge, while Beliefs about Consequences emerged as the primary enabler of attendance. Only around half of reported barriers and enablers were addressed by the invitation messages. Exploratory analyses found that fear was associated with lower intention to attend a TLHC appointment, yet none of the behaviourally informed messages appeared to reduce fear compared to the control message. ConclusionsImproving lung cancer screening uptake will likely require invitation messages that directly address emotional concerns, particularly fear, alongside credible recommendations. These findings highlight the importance of systematically aligning invitation message content with empirically identified behavioural influences when designing scalable interventions to improve lung cancer screening uptake. Contributions to the literatureO_LIAttendance at the NHS Targeted Lung Health Check remains low despite being a UK policy priority. This study provides evidence to inform invitation strategies for ongoing and future screening programmes. C_LIO_LIBehavioural economics frameworks are widely used in health messaging but lack systematic methods for linking behavioural influences with intervention content and evaluation. C_LIO_LIThis study demonstrates how Behaviour Change frameworks can diagnose why behaviourally informed messages may fail, by assessing alignment between intervention content and population-specific barriers and enablers. C_LIO_LIFindings suggest that messaging interventions targeting lung cancer screening attendance may have limited impact when they do not address emotional and social influences. C_LI