Aims
The purpose of this systematic review and meta-analysis was to investigate the effects of family-based health promotion interventions on child-level risk factors for type 2 diabetes in vulnerable families.

Methods
The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist for systematic reviews formed the methodological framework. CINAHL, Embase, MEDLINE, PsycINFO, and Web of Science were searched on January 12, 2024. The NTP-OHAT Risk of Bias Assessment Tool was used to assess the risk of bias in the individual studies, and meta-analyses were performed.

Results
The 4723 studies were identified, and 55 studies met the inclusion criteria. Results showed significant effects on children's body mass index (mean difference [MD], −0.18, 95% CI [−0.33 to −0.03], p = 0.02), body fat percentage (MD, −2.00, 95% CI [−3.31 to −0.69], p = 0.003), daily activity (standardized mean difference [SMD], 0.23, 95% CI [0.01; 0.44], p = 0.04), physical activity self-efficacy (SMD, 0.73, 95% CI [0.36 to 1.10], p < 0.01), intake of snacks (MD, −0.10, 95% CI [−0.17 to −0.04], p = 0.002), and sugar-sweetened beverages (SMD, −0.21, 95% CI [−0.42 to −0.01], p = 0.04). Subgroup analyses suggested that interventions aiming to change child and parent behavior simultaneously have larger effect on fasting glucose and nutrition consumption, and that interventions longer than 26 weeks have larger effects on body composition and physical activity behavior than shorter interventions.