Designing a Smoking Intervention for Youth Smokers

Phase 1 Q-method outcomes The outcomes of Phase 1 of this study will be Q-sorts completed by participants which will be inter-correlated producing a matrix for factor rotation and automatic flagging, and the z-score and the factor of the Q-sorts will be calculated.

The tobacco epidemic remains a pressing global health challenge, with tobacco-related illness contributing significantly to a high death rate worldwide. Smoking is the predominant mode of tobacco consumption worldwide and serves as the driving force behind this epidemic. According to the World Health Organization, there are an estimated 1.3 billion tobacco users worldwide currently. In Hong Kong, the smoking rate is estimated to be around 9.5%, with approximately 580 000 daily smokers in 2021. Despite the rate has decreased significantly from 23.3% in 1982, the Hong Kong government aims to further reduce the prevalence from 9.5% to 7.8% in 2025. The high prevalence of smoking imposes a significant public health burden worldwide, with tobacco use killing up to 50% of its users. Additionally, smoking causes cancers, stroke, cardiovascular diseases and respiratory diseases, with around 7000 deaths reported each year. One approach to reduce the smoking prevalence is to promote smoking cessation (SC) treatment among current smokers.

Young smokers constitute a large cohort of new smokers every year. It is estimated that up to 90% of daily smokers first tried smoking before 18 years old. Published studies consistently highlight the concerning prevalence of youth smoking within Hong Kong's community. Data from the recent school survey highlighted that despite only 1.2% of secondary school engages in smoking, a significant portion (7.4%, equivalent to around 24 000 students) of the youth population have previously engaged in smoking behaviour. The rate of youth ever smokers remain high at 7.4% in Hong Kong, equivalent to approximately 24 000 secondary school students, suggesting that youths are eagerly experimenting. This is also evident in the high prevalence of youths trying other tobacco products such as e-cigarettes or heated tobacco products, from 57.4% (178/310) in 2017 to 2018 to 85.9% (243/283) in 2019 to 2020. The shift from occasional smoking to dependency in youth is a crucial stage, making the adolescent years a key period for understanding and addressing smoking behaviours. It represents a key window for targeted interventions to prevent the progression towards regular smoking habits.

Smoking imposes severe health risks and long-term consequences. Effects of tobacco are well demonstrated including the effects of nicotine on brain development. The prevalence of tobacco use among youths not only jeopardizes their immediate health but negatively impacts their future well-being. Moreover, observations from Hong Kong further emphasize the pressing need for effective SC initiatives tailored to the unique needs of youths. The multifaceted challenges such as peer pressure and social influences are faced by struggling youths.

In response to these identified needs, it is imperative to develop comprehensive youth-orientated SC programs that encompass various aspects of prevention, intervention and support. Evidence-based strategies such as counselling services have shown promising outcomes in promoting smoke-free lifestyles among youths. Additionally, collaborations among healthcare institutions, government agencies and community organizations are crucial for maximizing the reach and effectiveness of cessation efforts. By addressing the health needs of local community through targeted youth SC initiatives, the investigators can significantly mitigate the adverse health effects of tobacco use among Hong Kong's young population.

Phase 3 Randomized control trial outcomes The primary outcomes of Phase 3 of this study will be smokers' (1) self-reported abstinence in the past 30 days at 2-month follow-up; (2) iScreen OFD Cotinine Saliva Test Kit (\<30ng/ml) biochemical validated tobacco abstinence; (3) the difference of the feasibility and acceptability score of the typology-based intervention between the intervention and control group.

• Time required for the counselling [Time frame: End of all follow-up (approximately 6 month)]
• Compliance rate of the SC counsellors in following the intervention protocol [Time frame: End of all follow-up (approximately 6 month)]
• Proportion of screened clients who participate in the RCT [Time frame: End of all follow-up (approximately 6 month)]
• Dropout rate of the participants who consent to the RCT [Time frame: End of all follow-up (approximately 6 month)]
• Satisfaction on the SC counsellors [Time frame: 2 months]
• Satisfaction on the AI chatbot and the chatbot initiated e-messages [Time frame: 2 months]
• Frequency of reading the chatbot initiated e-messages [Time frame: 2 months]
• Perceived effectiveness on the intervention [Time frame: 2 months]
• Satisfaction on the enrolment procedures [Time frame: 2 months]
• Intention to recommend the intervention to other smokers [Time frame: 2 months]
• Satisfaction about the intervention from SC counsellor [Time frame: End of all follow-up (approximately 6 month)]
• Perceived appropriateness of the intervention length from SC counsellor [Time frame: End of all follow-up (approximately 6 month)]