Cities for Better Health Childhood Obesity Prevention Initiative in JAPAN

NCT07061665 | Not Yet Recruiting

• 1 other identifier: M10825
• Study Type: interventional
• Target: 2,200
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Quality of Life (QOL); Nutrition; Physical Activity; Obesity; Childhood Obesity

Keywords

BMI; Childhood obesity; Japan; Chiba city; physical activity; nutrition; health equity; community intervention; randomized controlled trial; KIDSCREEN-10; Diet Quality Questionnaire

Outcome Measures

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.

  Baseline, 1-year follow-up, 2-year follow-up (2025-2027)

Secondary Outcomes (1)

• Health-Related Quality of Life (HRQoL)

  Baseline, 1-year follow-up, 2-year follow-up (2025-2027)

Other Outcomes (2)

• Physical Activity

  Baseline, 1-year follow-up, 2-year follow-up (2025-2027)

• Diet

  Baseline, 1-year follow-up, 2-year follow-up

Study Arms (2)

Intervention Group

EXPERIMENTAL

11 Junior High School District (JHSD) clusters in Chiba City receive a multi-level, multi-component intervention targeting individual, environmental, and community factors for childhood obesity prevention.

Behavioral: Multi-level, Multi-component Intervention Package

Control Group

NO INTERVENTION

11 Junior High School District clusters in Chiba City serve as a comparator, continuing usual practices without new obesity prevention interventions from the study.

Interventions

Multi-level, Multi-component Intervention Package BEHAVIORAL

The CBH COPI intervention applies multi-level strategies to improve children's environments and foster healthy behaviors. In schools, activities include schoolyard enhancements (e.g., hopscotch), inter-school sports events, nutrition lectures, healthy snacks, and educational materials linking health and academics. In parks and roads, improvements include cycling/walking promotions, signage, healthier vending machines, and community events. Supermarkets support healthy choices through menu information, loyalty incentives, cooking classes, product placement, and healthy food sales. At home and in communities, the Min-Challe app supports habit formation, with athletes, mascots, and ambassadors promoting healthy living. The coordinated program aims to naturally promote healthy eating, physical activity, and sustained lifestyle change among children aged 6-12 in Chiba City.

Intervention Group

Eligibility Criteria

• Age: 6 Years - 12 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• 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.
• Participants must not have any medical conditions that would preclude safe participation in routine physical activities promoted by the intervention.

You may not qualify if:

• 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.
• Families planning to relocate outside of Chiba City during the study period, making follow-up assessment infeasible.

Sponsors & Collaborators

• Chiba University: lead
• Novo Nordisk A/S: collaborator
• The Behavioural Insights Team: collaborator
• Delivery Associates: collaborator

Study Sites (1)

Chiba University

Chiba, Chiba, 263-8522, Japan

Location

MeSH Terms

Conditions

Motor Activity; Obesity; Pediatric Obesity

Condition Hierarchy (Ancestors)

Behavior; Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Atsushi Nakagomi, MD, PhD

CONTACT

+81-43-290-3177; anakagomi0211@chiba-u.jp

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Model Details: This study employs a parallel interventional design. Participants, grouped by 22 school clusters (Junior High School Districts), are assigned to either an intervention group or a control group for the duration of the study. The intervention group receives a multi-level, multi-component program aimed at childhood obesity prevention, while the control group continues with usual practice. Data will be collected through repeated cross-sectional surveys at baseline, 1-year, and 2-year follow-up. Statistical analyses will use ANCOVA models, adjusted for baseline outcomes and clustering.

Study Record Dates

• First Submitted: July 2, 2025
• First Posted: July 11, 2025
• Study Start: July 1, 2025
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): September 1, 2027
• Last Updated: July 11, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL

Locations

JP (1)