Clinical Research Directory

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.

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.

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.

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.

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, at the 1- and 2-month follow-ups, assist participants in booking or rebooking appointments if necessary. Investigators shall liaise with existing service providers and seek their assistance in promptly supporting our smokers.

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.

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.

WhatsApp messages on follow-up survey reminders.