Cities for Better Health Childhood Obesity Prevention Initiative in JAPAN
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age6-12
SponsorChiba University
About this trial
The goal of this interventional study is to prevent childhood obesity in children aged 6-12 years in Chiba City, Japan. The main questions it aims to answer are:
* Does the multi-component intervention for environments around children reduce the BMI z-score of children aged 6-12 years after one and two years? * Does the multi-component intervention for environments around children improve the health-related quality of life (assessed by KIDSCREEN-10) of children aged 6-12 years after one and two years?
Researchers will compare school clusters receiving the intervention to control clusters to see if the intervention package promotes healthy eating, increases physical activity, improves health-related quality of life, and reduces obesity prevalence.
Participants will:
* Attend elementary schools within participating clusters (either the intervention or control group). * Have baseline data collected, with follow-up assessments after one year and two years. * Potentially participate in school-based programs (nutrition education, physical activity promotion) and community-based initiatives (park activation, supermarkets) if in an intervention cluster. * Have their physical activity and dietary behavior assessed through self-report questionnaires.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Children aged 6 to 12 years who are currently enrolled in one of the public elementary schools located within the 22 participating Junior High School District clusters in Chiba City.
The parent or legal guardian of each child must provide written informed consent prior to participation.
Parents or legal guardians must have sufficient Japanese language proficiency to understand study procedures, complete questionnaires, and provide accurate information during the study.
Children must be physically and cognitively capable of participating in school- and community-based activities involved in the intervention.
Disqualifiers
Children whose parents or legal guardians fail to provide complete informed consent.
Families who withdraw consent at any point during the study period.
Children who independently express refusal to participate, even with parental consent.
Children with serious physical, psychological, or developmental disorders that prevent them from participating safely in the program's activities.
Trial design
Design model
Parallel
Treatments tested in this trial
Multi-level, Multi-component Intervention Package
BehavioralThe CBH COPI intervention applies multi-level strategies to improve children's environments and foster healthy behaviors. The coordinated program aims to naturally promote healthy eating, physical activity, and sustained lifestyle change among children aged 6-12 in Chiba City.
Elementary schools
BehavioralIn consultation with each elementary school, initiatives related to physical activity and diet will be implemented within the scope of the national curriculum guidelines. Super Hopscotch: Install foot-shaped signs and other markings on outdoor surfaces between the entrance/exit and school gates, as well as in the gymnasium-areas children frequent during daily school life. Place guides nearby explaining how to play and indicating difficulty levels, creating a safe and enjoyable play space. Playground Equipment Completion Card: Place numbered stickers on each piece of playground equipment, matching them to numbers on the completion card. Calendar-style Playground Equipment Completion Cards are distributed to children, who check off the numbers of the equipment they played on each day. Bug \& Find Journal: Distribute sketchbook-style "Bug \& Find Journals" to children. They sketch insects or flowers found that day.
Parks
BehavioralIn consultation with Chiba City, an environment that naturally encourages healthy choices will be fostered through modifications to city-managed facilities and awareness campaigns. Standing long jump: Mark a measurable distance for standing long jump on the pavement to create a fun and challenging environment. Slalom (line walking/running): Draw lines using shapes such as triangles, circles, and squares to create a path where children can walk or run along the line. Footprint maze: Children follow colored lines and shapes drawn on the ground to reach a goal, combining visual cues with physical movement. One-leg walking (balance walking): Place footprints on a curb about 10-20 cm wide, allowing children to move forward by alternating one leg along the footprints. Stair climbing: Display multiplication tables, English words, or phrases on the risers or sides of stairs to encourage children to climb them. And 25 m run, Hopscotch, Target throwing.
Ambassador Program
BehavioralChildren learn about food and lifestyle habits on their own, put them into action, and spread what they learn in the program to their families, schools, and communities. Target participants: Approximately 20 fourth- and fifth-grade elementary school students. Program components: * Learn \& Think: Understand the fundamentals of nutrition and the importance of healthy eating. * Experience: Apply nutrition knowledge through hands-on food-related activities. * Share \& Inspire: Communicate what they have learned and encourage healthy eating among peers and family members.
Home
BehavioralIn consultation with each elementary school or community partner, support will be provided to foster healthy habits within each household. •Provide tools to manage lifestyle habits, including the habit-forming app "Min-Challe," which allows anonymous teams of up to five users with a shared goal to report their daily achievements to each other by sharing photos (https://minchalle.com/).
Chiba University Academy
BehavioralTarget participants: Students from the intervention schools and the Chiba University Elementary School. * Three lectures are planned. * A Ken-Ken-Pa (hopscotch) course will be installed at the affiliated elementary school, or a simplified mat version will be used for hands-on activities. * An experiential booth will allow participants to experience the intervention components, with the aim of increasing the intensity and engagement of the intervention.
Treatment groups
2,200 Participants
are divided into 2 treatment groupsGroup A: Obesity Prevention Intervention GroupExperimental treatment 6 interventions
Group B: Control GroupNo intervention 0 interventions
Trial outcomes
Primary outcomes
1
Body mass index z-score (BMI-z) adjusted for age and sex
The primary outcome is the BMI z-score, calculated using the WHO 2007 Growth Reference. This metric standardizes a child's relative weight status by adjusting for both age and sex, enabling comparisons across different age groups and sexes. It represents the number of standard deviations a child's BMI is from the mean BMI of a healthy reference population. The BMI z-score allows for monitoring obesity-related changes over time and assessing the intervention's effectiveness in preventing excessive weight gain. The use of this z-score ensures consistency with international standards, facilitating global comparison of childhood obesity trends. The analysis will focus on changes in BMI z-score from baseline to 1-year and 2-year follow-ups. The BMI z-score is a continuous measure without a fixed minimum or maximum; lower values indicate lower relative adiposity, so a decrease (or a smaller increase) represents a more favorable outcome for obesity prevention.
Time frame
Baseline, 1-year follow-up, 2-year follow-up (2025-2027)Secondary outcomes
1
Health-Related Quality of Life (HRQoL)
HRQoL will be assessed using the KIDSCREEN-10 index, a validated, self-reported measure capturing children's subjective well-being across physical, emotional, social, and school functioning. This 11-item scale uses a 5-point Likert response for each item, which is then converted into a standardized T-score, further transformed to a 0-100 scale. On this scale, higher scores indicate better perceived quality of life. Changes in KIDSCREEN-10 scores will be tracked from baseline through 1-year and 2-year follow-ups to evaluate the intervention's impact on children's overall well-being.
Time frame
Baseline, 1-year follow-up, 2-year follow-up (2025-2027)Other outcomes
1
Physical Activity
Physical activity will be assessed using self-reported daily minutes of moderate-to-vigorous physical activity (MVPA) and sedentary screen time. Participants will report time spent in activities such as sports, cycling, or active play, as well as screen-based sedentary behaviors. Data will be collected at baseline, 1-year, and 2-year follow-ups to evaluate the intervention's impact on physical activity patterns and sustained behavioral changes. Interpretation will be guided by international guidelines on daily activity targets. Physical activity is reported in minutes per day (no fixed maximum). Higher moderate-to-vigorous physical activity (MVPA) indicates a better outcome, whereas higher sedentary screen time indicates a worse outcome.
Time frame
Baseline, 1-year follow-up, 2-year follow-up (2025-2027)2
Diet
Dietary outcomes will be assessed using the adapted Diet Quality Questionnaire (DQQ). This questionnaire evaluates children's usual intake of key food groups and dietary patterns. Participants or guardians will report the frequency of consuming various categories, including fruits, vegetables, whole grains, protein sources, dairy products, snacks, and sugary drinks. The DQQ aligns with global dietary guidelines and calculates scores reflecting dietary diversity and balance. Data will be collected at baseline, 1-year, and 2-year follow-ups to assess changes in dietary habits and the intervention's effects on promoting healthier eating patterns. The DQQ diet-quality score ranges from 0 to 18; higher scores indicate better diet quality (greater dietary diversity and adherence to dietary guidelines.
Time frame
Baseline, 1-year follow-up, 2-year follow-upSponsors and contacts
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Source ClinicalTrials.gov