Abstract
BACKGROUND: Inequity in child development is found at early age, but limited evidence exists on whether these gaps change over time and what are the mediators. OBJECTIVE: We aim to (1) quantify wealth related gaps in cognitive and socio-emotional development in early and middle childhood; (2) examine how these gaps were mitigated by maternal, child factors and home environment. METHODS: We assessed the offspring of women who participated in a randomized controlled trial of preconception micronutrient supplementation in Vietnam (n = 1599). Child development was measured by the Bayley Scales of Infant Development-III (at 1-2y) and the Wechsler Intelligence Scale for Children®-IV (at 6-7y). We used multivariable regression to estimate the changes in wealth gaps for child development over time, adjusting for potential factors that potentially influence cognitive development. RESULTS: We found significant wealth gaps in cognitive development during early childhood (gaps between top and bottom quintiles: 0.5 SD); these gaps increased substantially in middle childhood (0.9 SD). Wealth disparity in social emotion did not change over time (0.26-0.28 SD). Maternal factors, quality of home environment, and child nutritional status mitigated the wealth gap in cognitive development (7-42%) in early childhood. The contribution of these mitigating factors was smaller in middle childhood (2- 15%). Wealth gap in social emotion reduced by 13% and 43% among children with better nutritional status at 2y and higher quality of home environment at 6-7y, respectively. CONCLUSION: Interventions focusing on improving quality of home environment, maternal education, wellbeing, and child nutrition status may help reduce developmental deficits associated with poverty.