The study is to explore the understanding of the perception, risk behaviour, and attitudes related to non-communicable diseases among adolescents and young adults. The objectives of the study are:

1. To investigate the understanding of non-communicable diseases among adolescents and young adults;
2. To identify the prevalence of health-risk behaviours among adolescents and young adults;
3. To examine the attitudes and behaviours to prevent non-communicable diseases among adolescents and young adults

Chronic diseases, also known as non-communicable diseases (NCDs), are the leading causes of global morbidity and mortality, accounting for around 74% of all deaths worldwide. Cardiovascular diseases, cancers, chronic respiratory diseases, and diabetes contribute to over 80% of premature NCD-related deaths. The World Health Organization identifies four key modifiable behavioural risk factors-tobacco use, harmful alcohol consumption, unhealthy diets, and physical inactivity-as major contributors to NCDs. Evidence shows that most premature deaths from NCDs are preventable through targeted interventions and sustainable lifestyle changes. In Hong Kong, the burden of NCDs is growing, driven by an aging population. The Hospital Authority projects a 50% increase in NCD cases among the middle-aged, rising from 2 million in 2019 to 3 million by 2039, posing a serious challenge to the healthcare system. In response, the government has pledged to strengthen district-based primary healthcare services, including establishing health centres across all districts and launching the Chronic Disease Co-Care Pilot Scheme in 2023 for adults aged 45 and above.

However, adolescence represents a critical developmental window characterized by rapid biological, cognitive, and emotional changes, as well as heightened exposure to social stressors. This stage is particularly vulnerable to the adoption of risk behaviours that often persist into adulthood and contribute to chronic health conditions. Notably, 97.4% of smokers in Hong Kong began smoking before age 30, underscoring the importance of early intervention. These findings highlight the need to initiate education and screening efforts at a younger age. The adage "an ounce of prevention is worth a pound of cure" is especially pertinent in public health. Reflecting this, the Hong Kong Government is transitioning its healthcare model from treatment-focused to prevention-oriented. Prioritizing early intervention during youth is essential for promoting lifelong health and well-being and represents one of the most effective strategies for reducing the prevalence of NCDs in Hong Kong.

Aim of Study

The aim of the study is to explore the understanding of the perception, risk behaviour, and attitudes related to non-communicable diseases among adolescents and young adults. The objectives of the study are:

1. To investigate the understanding of non-communicable diseases among adolescents and young adults;
2. To identify the prevalence of health-risk behaviours among adolescents and young adults;
3. To examine the attitudes and behaviours to prevent non-communicable diseases among adolescents and young adults

Outcome measures Primary outcomes: Information on four major health-risk behaviours including tobacco use, harmful use of alcohol, an unhealthy diet and physical inactivity, and lifestyle practices associated with prevention and control of non-communicable diseases (NCDs)

In what way will the research contribute to knowledge or healthcare development? The findings of this study will contribute to the development of appropriate interventions that targeting adolescents and young adults with health-risk behaviours with the aim to help them quit health-risk behaviours and adopt a healthy lifestyle.

Study subjects Inclusion criteria

1. Aged 18 to 45 years
2. Able to speak Cantonese

Exclusion criteria

1. Studying medical, nursing and healthcare-related courses or working in medical, nursing, and allied health fields
2. Those who had been diagnosed with NCDs

How will subjects be identified and recruited: To enhance the representativeness of the sample, we aim to recruit participants from all the 18 districts in the community.

Measures: A modified behavioural health-risk factor survey was used to collect demographic data and information regarding health-risk behaviours. The survey was a checklist adopted from the Hong Kong Department of Health (www.chp.gov.hk/files/pdf/brfs\_2015apr\_en.pdf, accessed on 5 January 2021).

Methods of Data Analysis Data will be entered into SPSS for Windows (version 28). A logic check program will be installed for entry validation. Descriptive statistics such as frequency, percentage, and mean will be used to summarize the outcomes and other variables. Chi-square tests and t-tests will be used to compare outcome variables between subgroups. The Pearson product moment correlation coefficient will be used to investigate the interrelationships.

Inclusion Criteria:

• (1) Aged 18 to 45 years
• (2) Able to speak Cantonese

Exclusion Criteria:

• (1) Studying medical, nursing and healthcare related courses or working in medical, nursing, and allied health fields
• (2) Those who had been diagnosed with non-communicable diseases

About 5,000 young adults in Hong Kong without non-communicable diseases