Early Life Child Micronutrient Status, Maternal Reasoning, and a Nurturing Household Environment have Persistent Influences on Child Cognitive Development at Age 5 years: Results from MAL-ED

Abstract

Background: Child cognitive development is influenced by early-life insults and protective factors. To what extent these factors have a long-term legacy on child development and hence fulfillment of cognitive potential is unknown.

Objective: The aim of this study was to examine the relation between early-life factors (birth to 2 y) and cognitive development at 5 y.

Methods: Observational follow-up visits were made of children at 5 y, previously enrolled in the community-based MAL-ED longitudinal cohort. The burden of enteropathogens, prevalence of illness, complementary diet intake, micronutrient status, and household and maternal factors from birth to 2 y were extensively measured and their relation with the Wechsler Preschool Primary Scales of Intelligence at 5 y was examined through use of linear regression.

Results: Cognitive T-scores from 813 of 1198 (68%) children were examined and 5 variables had significant associations in multivariable models: mean child plasma transferrin receptor concentration (β: -1.81, 95% CI: -2.75, -0.86), number of years of maternal education (β: 0.27, 95% CI: 0.08, 0.45), maternal cognitive reasoning score (β: 0.09, 95% CI: 0.03, 0.15), household assets score (β: 0.64, 95% CI: 0.24, 1.04), and HOME child cleanliness factor (β: 0.60, 95% CI: 0.05, 1.15). In multivariable models, the mean rate of enteropathogen detections, burden of illness, and complementary food intakes between birth and 2 y were not significantly related to 5-y cognition.

Conclusions: A nurturing home context in terms of a healthy/clean environment and household wealth, provision of adequate micronutrients, maternal education, and cognitive reasoning have a strong and persistent influence on child cognitive development. Efforts addressing aspects of poverty around micronutrient status, nurturing caregiving, and enabling home environments are likely to have lasting positive impacts on child cognitive development.

Keywords: cognitive development; diarrhea; dietary intake; home environment; illness; micronutrients.

FIGURE 1

Selection of candidate variables from data collected in children and their mothers in The Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development Project (MAL-ED). ¹Ownership of agricultural land, ownership of a separate kitchen, floor and roof materials, the type of stove, water treatment and source of drinking water and hygiene, hand washing after going to the toilet, before food preparation and after the child defecates, mean monthly household income, years of maternal education, and the number of a defined list of assets. The HOME environmental safety variable was highly correlated with the child cleanliness variable and therefore dropped. ²Calcium, copper, iron, manganese, magnesium, potassium, and phosphorous, vitamins A, C, and E, total fat and saturated fats, protein from dairy and carbohydrate. ³Surveillance detections of A. lumbricodes (low prevalence), and the total number of pathogens because of correlation with bacterial pathogens. ⁴The number of observations of anemia, high transferrin receptor or low ferritin. ⁵The proportion of days with antibiotic given. ⁶The child's weight at 60 mo and at enrolment and the mother's depressive symptoms (from 6 to 8 mo). Anemia at 60 mo was also assessed, but was not significant in the univariate model.

FIGURE 2

Results of the multivariable model (n = 813 children) showing the mean effects and 95% CI for associations between early life risk factors and cognitive development scores at age 5 y in children from The Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) Project. HOME, Home Observation for Measurement of the Environment; NEO, neopterin; TfR, transferrin receptor.

FIGURE 3

Difference in the predicted marginal difference in Wechsler Preschool and Primary Scale of Intelligence (WPPSI) scores at 5 y if individual variables are set at their respective 10th (open circle) or 90th (closed dot) observed percentile compared to the marginal mean. HOME, Home Observation for Measurement of the Environment; NEO, neopterin; TfR, transferrin receptor.