Two-year impact of community-based health screening and parenting groups on child development in Zambia: follow-up to a cluster-randomized controlled trial

Background: Early childhood interventions have potential to offset the negative impact of early adversity. We evaluated the impact of a community-based parenting group intervention on child development in Zambia. Methods and Findings: We conducted a non-masked cluster-randomized controlled trial in Southern Province, Zambia. Thirty clusters of villages were matched based on population density and distance from the nearest health center, and randomly assigned to intervention (15 clusters, 268 caregiver-child dyads) or control (15 clusters, 258 caregiver-child dyads). Caregivers were eligible if they had a child six to 12 months old at baseline. In intervention clusters, caregivers were visited twice per month during the first year of the study by Child Development Agents (CDAs) and were invited to attend fortnightly parenting group meetings. Parenting groups selected 'head mothers' from their communities who were trained by CDAs to facilitate meetings and deliver a diverse parenting curr...