Cities for Better Health Childhood Obesity Prevention Initiative in JAPAN

N/ANot Yet RecruitingNCT07061665

Chiba University2,200 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

NONE

Enrollment

2,200

Conditions

Quality of Life (QOL)Nutrition

Interventions

Multi-level, Multi-component Intervention PackageBEHAVIORAL

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.

Eligibility

Sex: ALLMin age: 6 YearsMax age: 12 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * 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. Exclusion Criteria: * 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.

Outcomes

Primary Outcomes

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.

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

Secondary Outcomes

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.