Gen AI Powered Behavioral Support Plus Chewing Gum Intervention for Construction Workers Who Smoke: A Pragmatic, Pilot, Cluster Randomized Controlled Trial

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

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)

Study Overview

• Status: Not yet recruiting
• Conditions: Smoking Cessation
• Intervention / Treatment: Behavioral: Self-help smoking cessation booklet; Behavioral: AWARD advice; Behavioral: Referral card; Behavioral: Brief leaflet on health warning and smoking cessation; Drug: 1-week nicotine gum; Behavioral: 3-week chewing gum; Behavioral: 12-week chatbot-based instant messaging support; Behavioral: Brief video

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.

• Study Type: Interventional
• Enrollment (Estimated): 200
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Man Ping Wang, PhD; Phone Number: +852 3917 6636; Email: mpwang@hku.hk
• Study Contact Backup: Name: Mengyao Li, Mphil; Phone Number: +852 6851 8462; Email: lmy0814@connect.hku.hk

Study Locations

• Hong Kong
  • Hong Kong
    • Hong Kong, Hong Kong, Hong Kong, 999077
      • Hong Kong Council on Smoking and Health (COSH)
      • Contact: Fung Wong; Phone Number: +852 2180 5186
      • Sub-Investigator: Tai Hing Lam, MD
      • Sub-Investigator: Tzu Tsun Luk, PhD
      • Sub-Investigator: Xiaoyun Xie, MPH
      • Sub-Investigator: Mengyao Li, Mphil
      • Sub-Investigator: Ziqiu Guo, PhD
      • Sub-Investigator: Yilan Wu, Mphil

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

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

Exclusion Criteria:

1. Smokers who are participating in other smoking cessation programmes
2. Smokers who are using any smoking cessation medication
3. 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Health Services Research
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention group	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.; 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: 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: 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.; 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 participants to reduce smoking or make a quit attempt when using NRT.; 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 model (Relevance, Risks, Rewards, Roadblocks, Repetition), as used in our previous telephone-counselling trials and recommended by WHO for brief SC intervention.; 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.
Active Comparator: Control group	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.; 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: 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: 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.; 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 participants to reduce smoking or make a quit attempt when using NRT.; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Biochemically validated abstinence	Defined as exhaled CO level <4ppm and saliva cotinine level ≤30 ng/ml	6-month follow-up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Biochemically validated abstinence	Defined as exhaled CO level <4ppm and saliva cotinine level ≤30 ng/ml	3-month follow-up
Self-reported 7-day point prevalence abstinence	Smokers who did not smoke even a puff in the 7 days preceding the follow-up	3- and 6-month follow-ups
Self-reported reduction	Defined by at least 50% reduction in baseline daily number of cigarettes	1-, 2-, 3- and 6-month follow-ups
Self-reported use of smoking cessation service	Use of smoking cessation service at 1-, 2-, 3- and 6-month follow-ups.	1-, 2-, 3- and 6-month follow-ups
Family well-being	Family well-being will be assessed using the 3H scale, which measures perceived family health, happiness, and harmony on a 0-10 scale.	3- and 6-month follow-ups
Perceived family happiness	Perceived family happiness will be measured using a single-item self-reported family happiness scale ranging from 0 to 10.	3- and 6-month follow-ups

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recruitment rate	Defined as the number of participants divided by the number of eligible smokers	Baseline
Retention rate	Defined as the number of participants who completed the follow-up divided by the number of participants	1-, 2-, 3- and 6-month follow-ups
Chatbot usability	Chatbot usability will be evaluated using the 11-item Bot Usability Scale (BUS), which assesses perceived effectiveness, efficiency, and satisfaction.	3-month follow-up
Acceptability of NRT sampling	Acceptability of NRT sampling will be assessed through 4 brief items (score range from 0 to10) on perceived usefulness for craving relief, perceived side effects, willingness to continue using NRT after the free sample, and overall satisfaction with the NRT gum.	1-, 2-, 3- and 6-month follow-ups
Acceptability of chewing gum	Acceptability of chewing gum will be assessed through 3 brief items (score range from 0 to 10) on perceived usefulness for behavioral substitution, perceived fit with construction worksite routines, and willingness to continue using chewing gum as a cessation aid.	1-, 2-, 3- and 6-month follow-ups
Self-reported adverse events	Self-reported adverse events related to nicotine gum and chewing gum will be assessed using a binary question: "Have you experienced any adverse events when using nicotine gum or chewing gum?"	1-, 2-, 3- and 6-month follow-ups

Collaborators and Investigators

• Sponsor: The University of Hong Kong
• Investigators: Principal Investigator: Man Ping Wang, PhD, The University of Hong Kong

Study record dates

Study Major Dates

• Study Start (Estimated): June 20, 2026
• Primary Completion (Estimated): May 31, 2027
• Study Completion (Estimated): June 30, 2027

Study Registration Dates

• First Submitted: June 9, 2026
• First Submitted That Met QC Criteria: June 9, 2026
• First Posted (Actual): June 15, 2026

Study Record Updates

• Last Update Posted (Actual): June 15, 2026
• Last Update Submitted That Met QC Criteria: June 9, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Chewing gum; Nicotine replacement therapy; Chatbot; Digital health; Large Language model; Construction worker
• Additional Relevant MeSH Terms: Behavior; Health Behavior; Smoking Cessation; Therapeutics; Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Carbohydrates; Polymers; Macromolecular Substances; Polysaccharides; Biological Products; Complex Mixtures; Biopolymers; Plant Gums; Plant Exudates; Candy; Tobacco Use Cessation Devices; Chewing Gum; Nicotine Chewing Gum
• Other Study ID Numbers: Build to Quit

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No