Design for a cluster randomized controlled trial to evaluate the impact of a school-based fruit and vegetable co-op on cardiometabolic health of children and parents in a persistent poverty area

BACKGROUND In 2022, the National Cancer Institute funded five centers nationally to prevent cancer in persistent poverty areas, including one in Houston, TX reducing obesity-related cancers in Acres Homes. This paper describes the design and framework of one of the center's research projects, a cluster-randomized controlled trial (CRCT) evaluating the impact of Brighter Bites (BB) nutrition intervention on child vegetable intake, glycosylated hemoglobin (HbA1c), and obesity among children in grades 1-3 from the Acres Homes region. METHODS In this CRCT, 12 schools serving under-resourced children in Acres Homes were recruited and randomized into intervention and wait-list control groups across two waves during the 2024-2025 and 2025-2026 school years. In Wave 1 (2024-2025), six elementary schools were randomized (3 intervention, 3 wait-list), enrolling eligible 1st-3rd graders (n = 360). Children in the intervention schools are followed for two school years, while children in wait-list schools are followed for one school year. Grounded in the Social Cognitive Theory, the BB intervention includes 16 bi-weekly distributions of 20-25 pounds of fresh produce, recipe tastings, and nutrition education for children and parents. Outcome evaluation included in-person assessment of child metabolic markers, height, weight, and skin carotenoid levels, as well as parent self-report surveys. Primary outcomes are child HbA1c and vegetable intake. Secondary outcomes included anthropometric and metabolic measures, household food security status, parent and child dietary behaviors, and home access/availability of fruit and vegetables. CONCLUSION This study will inform the implementation and evaluation of a school-based nutrition intervention to improve child nutrition and metabolic health outcomes. TRIAL REGISTRATION NUMBER The clinical trial was registered on clinicaltrials.gov (NCT06570707) before the start of recruitment.