This is a prospective cohort study building upon the existing cohort study on the effectiveness of the Trekkers Family Enhancement Scheme. This study will sample 200 low-income parent-child pairs and follow them up for 24 months with yearly assessment on parental stress and child health using both subjective measures and objective physiological parameters. Additional data on parenting style, neighbourhood cohesion, child physical assault and neglect potential, parental mental health and HRQOL and family disharmony will also be collected at each assessment time point for testing mediating and moderating mechanisms between parental stress and child health. The baseline assessment will be carried out in 2016-17 with three repeated assessments after 6 months, 12 months, and 24 months.

Study aims

• To examine the relationship between parental stress and child health.
• To evaluate the stress of parents as indicated by their subjective perception of mental health, quality of life and allostatic load on the body.
• To evaluate the health of children as indicated by their well-being, behaviors, body mass index (BMI) z-score and telomere length.
• To examine the correlation between changes in parental stress and changes in child health over time.
• To identify the moderators and mediators of the relationship between parental stress and child health.

Eligible participants in the main cohort study will be approached by call or during face-to-face sessions. Parents who express interest in participation will be provided with an information sheet about the research and asked to sign the consent form for themselves and for their children. After providing consent, the parent of each parent-child pair will complete a set of structured questionnaires on parental mental health and HRQOL, parenting style, neighborhood cohesion, and their children's well-being and behaviors. Physical examination including blood pressure, heart rate, weight, height, and waist-to-hip ratio will also be carried out on both parents and children. A swab of buccal cells will be taken from each child. Venous blood will be sampled from each parent.

This study will have four assessment waves: Baseline, T2 follow up (6 months), T3 follow up (12 months), and T4 follow up (24 months). Physical health data and biological samples will be collected by research nurses and research assistants during health assessment session held in community centers. Questionnaire data will be collected by trained interviewers during telephone survey. To minimize attrition, a package of questionnaires and a sheet of instructions and equipment (i.e. brushes) for swab-taking at home may also be sent to parents upon request.

Inclusion Criteria:

• Family monthly household income does not exceed 75% of Hong Kong's median monthly household income
• At least one parent and one child aged 6 to 16 years of the same family have given consent to participate in the main cohort study

Exclusion Criteria:

• Parents cannot speak or read Chinese;
• Children were born prematurely and/or with a congenital deformity; and
• Neither parent is the primary caregiver of the child.

Participants from low-income families will be recruited from the existing cohort study (main cohort study) on the effectiveness of the Trekkers Family Enhancement Scheme funded by a philanthropic foundation in Hong Kong (Kerry Group Kuok Foundation (Hong Kong) Limited).