RESUMO
OBJECTIVES: The majority of the evidence about the effectiveness of early parenting and nutrition interventions pertains to 1 targeted index child in a given household. We evaluated whether nontargeted sibling children benefited from a bundled parenting and nutrition intervention. METHODS: We designed a sub-study within a broader cluster-randomized trial that evaluated the effects of engaging both mothers and fathers and bundling parenting and nutrition interventions in Mara, Tanzania. Trained community health workers delivered interventions to parents through peer groups and home visits. Interventions encompassed various content including responsive parenting, infant and young child feeding, and positive couples' relationships. The main trial enrolled mothers and fathers and 1-index children <18 months of age in 80 clusters. Between June and July 2021, in 32 clusters (16 intervention, 16 control), we reenrolled 222 households (118 intervention, 104 control) from the main trial that had another child <6 years of age (ie, sibling to the index child). We compared caregiving practices and child development and nutrition outcomes among siblings in intervention versus control households. RESULTS: Compared with control siblings, intervention siblings had improved expressive language development (ß = 0.33 [95% confidence interval: 0.03 to 0.62]) and dietary intake (ß = 0.52 [0.10 to 0.93]) and reduced internalizing behaviors (ß = -0.56 [-1.07 to -0.06]). Intervention caregivers reported greater maternal stimulation (ß = 0.31 [0.00 to 0.61]) and paternal stimulation (ß = 0.33 [0.02 to 0.65]) and displayed more responsive caregiving behaviors (ß = 0.40 [0.09 to 0.72]) with sibling children. CONCLUSIONS: A father-inclusive, bundled parenting and nutrition intervention can achieve positive spillover effects on sibling children's developmental and nutritional outcomes.