Discussion
EARLY PREGNANCY
In this long-term follow-up study of an RCT that provided a comprehensive daily nutritional supplement during most of the first 1000 d, from early pregnancy to 18 mo postpartum, we did not find effects on social–emotional problems at age 9–11 y. Thus, the previous finding showing reduced social–emotional difficulties in the SQ-LNS group at age 4–6 y was not sustained to age 9–11 y. We did find that children who experienced less-enriched early childhood home environments tended to have higher social–emotional difficulties at age 9–11 y for 8 of the 23 social–emotional scores examined. These associations were attenuated, but 7 remained significant, when adjusting for concurrent home environment, which was significantly associated with 11 of the 23 social–emotional scores. Among children who experienced less-enriched early childhood home environments, those in the SQ-LNS group recorded 0.37 SD lower self-reported conduct problems than those in the control group. This is consistent with the previous finding at age 4–6 y in the same cohort that SQ-LNS buffered children from social–emotional difficulties associated with less-enriched home environments.To our knowledge, this is the first RCT in Africa to report a long-term follow-up assessment after nutritional supplementation with both macronutrients and micronutrients in both the prenatal and postnatal periods, which is a foundational period for brain development. We are aware of only 2 previous studies with a similar design, both of which were conducted in Latin America in the 1970s. One of these randomized only 4 villages to the intervention and control groups [The lack of overall effects of SQ-LNS on child social–emotional problems may have been due to the low prevalence of social–emotional problems at 9–11 y of age, such that there was little potential to benefit from early nutritional intervention at this age in this outcome domain. Few children (<2%) experienced high social–emotional difficulties on the parent-reported SDQ at 9–11 y, in contrast to the high prevalence on this measure at age 5 y in the same cohort (25%). As shown in The finding that a less-enriched home environment during both early and middle childhood was associated with higher child social–emotional problems is consistent with findings among children in high-income countries [Our hypothesis that greater effects of SQ-LNS would be found among children from less-enriched home environments was partly supported by the interaction found for self-report conduct problems. Among children in less-enriched early childhood home environments, those in the SQ-LNS group scored substantially lower than the control group (0.37 SD) in this domain. This pattern is consistent with developmental theories that posit that children who experience biological vulnerabilities may show similar outcomes compared with children without biological vulnerabilities when raised in positive environments but may falter under conditions of environmental stress [Strengths of the study were the individually randomized design, large number of children assessed 10 y after the trial was completed, balance of background characteristics between the intervention groups, a comprehensive assessment of various types of social–emotional problems using multiple tools and multiple respondents (self, parent, and teacher), and demonstrated reliability of the translated tools in the local context. One limitation was that those lost to follow-up differed significantly from those included in the analysis in gestational age at delivery and maternal parity. However, it is unlikely that this led to bias in the results because the difference in gestational age was small (38.9 vs. 39.3 wk) and there was no interaction between the intervention group and parity for most outcomes. Another limitation was that the minimum effect size we were able to detect with our sample size was 0.2 SD, whereas previous studies have shown positive effects of nutritional supplementation on developmental outcomes of ∼0.1 SD [Our study adds to the evidence base for the effectiveness of nutritional interventions such as SQ-LNS during the prenatal and postpartum periods. Although we did not find long-term effects on children's social–emotional problems, we found some evidence that there may be a positive effect among children in less-enriched home environments. Future work will examine other outcomes at this age, such as direct assessments of child behavior and physiology, and will follow up the cohort later in adolescence.