Promoting Smoking Cessation in the Community Via "Quit to Win" Contest 2026: Engagement-Focused GenAI-based Chatbot for Real-Time Smoking Cessation Support (QTW2026)

Building Capacity and Promoting Smoking Cessation in the Community Via "Quit to Win" Contest 2026: Real-time Smoking Cessation Instant Messaging Support Using a Engagement-Focused Large Language Model (LLM)-Based Chatbot

The goal of this trial is to learn if chatbot-based instant messaging works to help smoking cessation in general adult smokers. It will also learn about the experience, attitude, and perception of using an LLM-based chatbot. The main questions it aims to answer are:

1. Will an engagement-focused LLM-based chatbot smoking cessation intervention have a non-inferior validated abstinence rate than the control group?
2. Will an LLM-based chatbot smoking cessation intervention have a non-inferior self-reported abstinence rate, smoking reduction rate, and smoking cessation services use rate than the control group?

Researchers will compare an LLM-based chatbot smoking-cessation intervention to a human-led instant messaging support group (brief advice based on AWARD and personalised active referral) to determine whether chatbot-based instant messaging support promotes smoking cessation.

Participants in the intervention group will receive:

1. AWARD advice
2. Personalised active referral
3. 12 weeks of chatbot-based instant messaging support (via WhatsApp)

Study Overview

• Status: Not yet recruiting
• Conditions: Smoking Cessation
• Intervention / Treatment: Behavioral: Reminder messages; Behavioral: AWARD advice; Behavioral: Brief leaflet on health warning and smoking cessation; Behavioral: Referral card; Behavioral: Self-help smoking cessation booklet; Behavioral: Personalized active referral; Behavioral: 12 weeks of chatbot-based instant messaging support; Behavioral: 12 weeks of human-led instant messaging support

Detailed Description

Although smoking prevalence in Hong Kong has declined to 9.1% in 2023, achieving the government's target of 7.8% by 2025 remains a major public health challenge. Unassisted "cold turkey" quitting has a long-term success rate of less than 5%, whereas evidence-based behavioural and pharmacological interventions can raise success rates to approximately 20% or higher. However, existing cessation services in Hong Kong face a critical utilisation gap: only 17.5% of smokers have engaged with professional services, and merely 23% have used nicotine replacement therapy. This underutilisation suggests that traditional human-resource-intensive models may lack accessibility, scalability, and local appeal. Generative AI, particularly large language models, offers a transformative solution by delivering consistent, scalable, and personalised support. In the 2025 "Quit to Win" round, we integrated an LLM-based chatbot via WhatsApp and received positive qualitative feedback. Yet quantitative analysis revealed a sharp engagement decline, with weekly participation dropping from 32% in week 1 to 14% by week 12, indicating that conversational ability alone does not guarantee sustained user commitment. To address this implementation gap, we have developed an engagement-focused GenAI companion that incorporates structured onboarding, context-aware personalisation, multimodal (text/audio) input, empathetic support, habit-aligned reminders, localised humour, and gamified features such as success stories and knowledge quizzes. Therefore, our study aims to test, via a two-arm non-inferiority randomised controlled trial, the effectiveness of a comprehensive intervention combining brief cessation advice (AWARD), personalised active referral, and this engagement-enhanced GenAI chatbot support compared with human-led instant messaging counselling among current smokers who join the Quit to Win Contest across all 18 districts of Hong Kong.

• Study Type: Interventional
• Enrollment (Estimated): 998
• 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: Yilan Wu; Phone Number: +852 56497578; Email: visspalan@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: Man Ping Wang, PhD; Phone Number: +852 3917 6636; Email: mpwang@hku.hk
      • Sub-Investigator: Shengzhi Zhao, PhD
      • Sub-Investigator: Xiaoyun Xie, MPH
      • Sub-Investigator: Mengyao Li, Mphil
      • Contact: Yilan Wu; Phone Number: +852 56497578; Email: visspalan@connect.hku.hk
      • Principal Investigator: Man Ping Wang
      • Sub-Investigator: Ziqiu Guo, PhD
      • Sub-Investigator: Yilan Wu, MGH

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Hong Kong residents aged 18 years or above
2. Smoke at least one cigarette (including heated tobacco products) per day or use an e-cigarette daily in the preceding 3 months
3. Able to communicate in Cantonese (including reading and writing Chinese)
4. Saliva cotinine level ≥30 ng/mL
5. Intention to quit or reduce smoking
6. Have WhatsApp installed
7. Able to use WhatsApp for communication

Exclusion Criteria:

Currently participating in other smoking cessation programmes or using any smoking cessation drug

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: Reminder messages; WhatsApp messages on follow-up survey reminders.; Behavioral: AWARD advice; A brief (30-60 seconds) face-to-face or remote smoking cessation advice delivered using the validated AWARD model: Ask about smoking history; Warn about high health risks (accompanied by a health warning leaflet); Advise quitting as soon as possible and setting a quit date (to qualify for contest prizes); Refer to smoking cessation services using a referral card; Do it again - repeat the intervention at each follow-up, encouraging re-quitting after relapse or relapse prevention after success.; Behavioral: Brief leaflet on health warning and smoking cessation; A two-sided, colour-printed A4 leaflet covering: (1) absolute risk of death from smoking; (2) full list of diseases caused by active and second-hand smoking; (3) ten pictorial warnings of health consequences on one page for maximum impact; (4) benefits of smoking cessation; and (5) simple encouraging messages to quit.; Behavioral: Referral card; A three-folded card containing brief information and highlights of existing smoking cessation services in Hong Kong, contact methods, motivational messages, and strong supporting slogans.; Behavioral: Self-help smoking cessation booklet; A generic booklet provided covering: benefits of quitting, smoking-related diseases, methods to quit, how to handle withdrawal symptoms, a quitting declaration, and other practical tips.; Behavioral: Personalized active referral; Smokers will be introduced to various SC services in Hong Kong (via the referral card) and motivated to use them. Well-trained SC ambassadors will assist smokers in choosing their favourite or most convenient type of service. Research staff will assist participants in booking or re-booking the SC services at the 1- and 2-month follow-ups (after very brief questionnaire surveys). Participants' contact information will be forwarded to SC service providers within 7 days, and providers are expected to contact participants within 1-2 weeks. Research staff will also monitor participants' use of SC services at each follow-up (1-, 2-, 3-, and 6-month) and assist participants in booking or rebooking appointments if necessary at the 1- and 2-month follow-ups. We shall liaise with the existing service providers and seek their assistance in supporting our smokers in a timely manner.; Behavioral: 12 weeks of chatbot-based instant messaging support; Participants in the intervention group will receive 12 weeks of instant messaging support delivered by an LLM-based chatbot (GPT-4o or newer) on WhatsApp, supporting text and audio input. Using prompt engineering, agent techniques, and Retrieval-Augmented Generation, the chatbot delivers theory-based 5As/5Rs-structured interventions alongside freeform, on-demand support, with engagement features including personalisation, proactive check-ins, and interactive Quick Commands.
Active Comparator: Control group	Behavioral: Reminder messages; WhatsApp messages on follow-up survey reminders.; Behavioral: AWARD advice; A brief (30-60 seconds) face-to-face or remote smoking cessation advice delivered using the validated AWARD model: Ask about smoking history; Warn about high health risks (accompanied by a health warning leaflet); Advise quitting as soon as possible and setting a quit date (to qualify for contest prizes); Refer to smoking cessation services using a referral card; Do it again - repeat the intervention at each follow-up, encouraging re-quitting after relapse or relapse prevention after success.; Behavioral: Brief leaflet on health warning and smoking cessation; A two-sided, colour-printed A4 leaflet covering: (1) absolute risk of death from smoking; (2) full list of diseases caused by active and second-hand smoking; (3) ten pictorial warnings of health consequences on one page for maximum impact; (4) benefits of smoking cessation; and (5) simple encouraging messages to quit.; Behavioral: Referral card; A three-folded card containing brief information and highlights of existing smoking cessation services in Hong Kong, contact methods, motivational messages, and strong supporting slogans.; Behavioral: Self-help smoking cessation booklet; A generic booklet provided covering: benefits of quitting, smoking-related diseases, methods to quit, how to handle withdrawal symptoms, a quitting declaration, and other practical tips.; Behavioral: Personalized active referral; Smokers will be introduced to various SC services in Hong Kong (via the referral card) and motivated to use them. Well-trained SC ambassadors will assist smokers in choosing their favourite or most convenient type of service. Research staff will assist participants in booking or re-booking the SC services at the 1- and 2-month follow-ups (after very brief questionnaire surveys). Participants' contact information will be forwarded to SC service providers within 7 days, and providers are expected to contact participants within 1-2 weeks. Research staff will also monitor participants' use of SC services at each follow-up (1-, 2-, 3-, and 6-month) and assist participants in booking or rebooking appointments if necessary at the 1- and 2-month follow-ups. We shall liaise with the existing service providers and seek their assistance in supporting our smokers in a timely manner.; Behavioral: 12 weeks of human-led instant messaging support; Participants in the control group will receive 12 weeks of instant messaging support delivered by a trained human counsellor via WhatsApp. Using the same theoretical frameworks as the chatbot intervention, the counsellor will provide real-time behavioural and psychosocial support grounded in the 5As/5Rs models, Motivational Interviewing (MI), and evidence-based Behaviour Change Techniques (BCTs). The support will be personalised according to each participant's sociodemographic characteristics, smoking patterns, quit intentions, and plans.

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
Prolonged abstinence	Abstinence from smoking for 3 consecutive months at 3-month follow-up, or for 6 consecutive months at 6-month follow-up	3-month and 6-month follow-ups
Quit attempt	Abstinence for at least 24 hours	1-, 2-, 3-, and 6-month follow-ups
Post-cessation weight change	Self-reported change in body weight (in kilograms) from baseline to follow-up	6-month follow-up
Self-reported mental health conditions	Patient Health Questionnaire-4 (PHQ-4)	Baseline and 6-month follow-up
Self-reported smoking-related health conditions	Answer "Yes" to experiencing any smoking-related health condition during smoking cessation or reduction	Baseline and 6-month follow-up
Chatbot user experience	Chatbot Usability Scale	3-month follow-up

Collaborators and Investigators

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

Study record dates

Study Major Dates

• Study Start (Estimated): June 20, 2026
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): June 30, 2028

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: Smoking cessation; Engagement; Chatbot; Digital health; Large-language model
• Additional Relevant MeSH Terms: Behavior; Health Behavior; Smoking Cessation
• Other Study ID Numbers: QTW2026

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