Build to Quit 「築建無煙」: Gen AI Powered Behavioral Support Plus Chewing Gum Intervention for Construction Workers Who Smoke: A Pragmatic, Pilot, Cluster Randomized Controlled Trial

Hong Kong has achieved a sustained reduction in daily cigarette smoking, from 23.3% in the early 1980s to 8.5% in 2025. However, the current prevalence remains above the Government's Towards 2025 target of 7.8%, indicating the need for continued and targeted cessation efforts. The construction industry represents a particularly important setting for intervention, as recent legislative amendments to designate construction sites as no-smoking areas have further strengthened the policy basis for promoting smoke-free worksites.

Construction workers (CWs) are a high-priority population for smoking cessation because they have consistently higher smoking prevalence than many other occupational groups and the general population. In Hong Kong, a workplace health study found that 45% of construction workers were daily smokers, nearly twice the prevalence among office clerks/professionals. For CWs, smoking may compound existing occupational health risks by increasing susceptibility to respiratory and cardiovascular diseases in a physically demanding and dust-exposed work environment.

This study proposes a comprehensive worksite-targeted smoking cessation intervention model for CWs who smoke in Hong Kong, integrating NRT sampling, chewing gum support, and chatbot-delivered instant messaging. NRT is an evidence-based pharmacotherapy for reducing nicotine withdrawal symptoms and supporting smoking abstinence, and has been widely used in community-based cessation interventions. For CWs, short-term NRT sampling may provide immediate access to evidence-based pharmacological support, reduce early withdrawal symptoms, and lower the initial barrier to treatment uptake in a worksite setting. Chewing gum may complement NRT sampling by serving as a low-cost behavioral substitute for smoking, particularly by replacing the hand-to-mouth and oral routines associated with cigarette use. Chatbot-delivered instant messaging support can further extend the intervention beyond the worksite by providing 24/7 support, reminders for NRT and chewing gum use, and real-time assistance during cravings or high-risk smoking situations.