Gen AI Powered Behavioral Support Plus Chewing Gum Intervention for Construction Workers Who Smoke

Official title

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

Overview

The goal of this pilot trial is to learn if 1-week NRT sampling, 3-week chewing gum, and 12-week chatbot-delivered instant messaging support works to help smoking cessation in construction workers who smoke. It will also learn about the feasibility, acceptability, and preliminary effectiveness of delivering the comprehensive intervention in construction settings. The main questions it aims to answer are: 1. Will the integrated intervention, comprising NRT sampling, chewing gum, and chatbot-delivered instant messaging support, show feasibility, acceptability, and appropriateness for delivery in construction worksite settings? 2. Will participants who receive the comprehensive intervention have a higher validated abstinence rate than those who receive NRT sampling alone? Researchers will compare the integrated intervention, comprising NRT sampling, chewing gum, and chatbot-delivered instant messaging support, to the standard care group (NRT sampling alone) to see if the integrated intervention works to promote smoking cessation. Participants in the intervention group will receive: 1. AWARD advice and brief video 2. 1-week NRT sampling 3. 3-week chewing gum 4. 12-week chatbot-based instant messaging support (via WhatsApp)

Detailed description

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.

Interventions

• Behavioral AWARD advice
  AWARD advice include Ask about smoking history, Warn about the high risk, Advise to quit, Refer smokers to smoking cessation services (with a referral card), and Do it again.
• Behavioral Brief leaflet on health warning and smoking cessation
  The contents of the leaflet include (1) highlights of the absolute risk of death due to smoking; (2) the whole list of diseases caused by active and secondhand smoking; (3) ten horrible pictorial warnings of health consequences of smoking and second-hand smoking in one page to maximize the impacts; (4) benefits of SC and (5) simple messages to encourage participants to quit smoking.
• Behavioral Referral card
  The contents consist of brief information and a highlight of existing smoking cessation services, contact methods, motivation information and strong supporting messages or slogans.
• Behavioral Self-help smoking cessation booklet
  The contents include information about the benefits of quitting, smoking and diseases, methods to quit, how to handle withdrawal symptoms, declaration of quitting, etc.
• Drug 1-week nicotine gum
  Participants in both group will receive a 1-week supply of free nicotine gum (2 mg or 4 mg). The dosage of nicotine gum will be guided by participants' daily cigarette consumption, in accordance with recommendations from the Department of Health. Research assistants will explain the benefits of NRT for smoking cessation, provide instructions on the correct use of nicotine gum, encourage participants to continue using nicotine gum after completing the free sample where appropriate, and advise par
• Behavioral 3-week chewing gum
  Participants in the intervention group will receive 6 packs of chewing gum at baseline (2 packs per week). Chewing gum will be presented as a practical strategy to replace the hand-to-mouth and oral routines associated with smoking, particularly during work breaks, after meals, in other smoking-related situations at construction sites, or when participants are unwilling to use nicotine gum.
• Behavioral 12-week chatbot-based instant messaging support
  Participants in the intervention group will receive 12 weeks of instant messaging support delivered by the LLM-based chatbot accessible via WhatsApp platform. The chatbot, powered by Claude model (or more advanced model available) using prompt-engineering and agent-based techniques, will deliver theory-based and structured intervention alongside freeform, on-demand support. The structured intervention session deploys the 5As model (Ask, Advise, Assess, Assist, and Arrange follow-up) and 5Rs mode
• Behavioral Brief video
  Participants in both groups will receive a brief motivational video (15-second) via WhatsApp. The video will feature a construction worker who successfully quit smoking in our previous trial, providing a relatable peer role model for participants. The video will welcome participants to the programme, encourage them to make a quit attempt, and promote early use of nicotine gum as a practical strategy for managing cravings and supporting smoking cessation.

Primary outcome measures

• Biochemically validated abstinence [Time frame: 6-month follow-up]

Secondary outcome measures (6)

• Biochemically validated abstinence [Time frame: 3-month follow-up]
• Self-reported 7-day point prevalence abstinence [Time frame: 3- and 6-month follow-ups]
• Self-reported reduction [Time frame: 1-, 2-, 3- and 6-month follow-ups]
• Self-reported use of smoking cessation service [Time frame: 1-, 2-, 3- and 6-month follow-ups]
• Family well-being [Time frame: 3- and 6-month follow-ups]
• Perceived family happiness [Time frame: 3- and 6-month follow-ups]

Eligibility criteria

Inclusion criteria

• Hong Kong residents aged 18 or above
• Smoke at least one cigarette per day in the preceding 3-month
• Able to communicate in Cantonese (including reading and writing Chinese)
• Saliva cotinine 30 ng/ml or above
• Intent to quit / reduce smoking
• Have instant messaging tool (WhatsApp) installed
• Able to use instant messaging tool (e.g., WhatsApp) for communication.

Exclusion criteria

• Smokers who are participating in other smoking cessation programmes
• Smokers who are using any smoking cessation medication
• Smokers who are presenting with the following oral diseases, including recent oral surgery or tooth extraction, unstable dentures, significant tooth mobility or advanced periodontal disease, temporomandibular pain or dysfunction, or painful oral mucosal lesions

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Health services research

Study locations

Hong Kong · 1 center

• Hong Kong Council on Smoking and Health (COSH) — Hong Kong

Identifiers

NCT: NCT07649018 · Build to Quit

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗