Impact of early and concurrent stunting on cognition

Abstract

Undernutrition is associated with poor cognitive development, late entry into school, decreased years of schooling, reduced productivity and smaller adult stature. We use longitudinal data from 1674 Peruvian children participating in the Young Lives study to assess the relative impact of early stunting (stunted at 6-18 months of age) and concurrent stunting (stunted at 4.5-6 years of age) on cognitive ability. Anthropometric data were longitudinally collected for children at 6-18 months of age and 4.5-6 years of age at which time verbal and quantitative ability were also assessed. We estimate that an increase in concurrent height-for-age z-scores (HAZ) by one standard deviation was associated with an increase in a child's score on the Peabody Picture Vocabulary Test (PPVT) by 2.35 points [confidence interval (CI): 1.55-3.15] and a 0.16 point increase on the cognitive development assessment (CDA) (CI: 0.05-0.27). Furthermore, we report that the estimate for concurrent HAZ and PPVT is significantly higher than the estimate for early stunting and PPVT. We found no significant difference between early and concurrent estimates for HAZ and CDA. Children from older mothers, children whose mothers had higher education levels, children living in urban areas, children who attended pre-school, children with fewer siblings and children from wealthier backgrounds scored higher on both assessments. Cognitive skills of children entering school were associated with early stunting but the strongest association was found with concurrent stunting suggesting that interventions preventing linear growth faltering should not only focus on the under 2s but include children up to 5 years of age.

How consistent are associations between stunting and child development? Evidence from a meta-analysis of associations between stunting and multidimensional child development in fifteen low- and middle-income countries

“…To our K a z a k h s t a n P a k i s t a n ( B l o c h i s t a n ) S u r i n a m e S w a z i l a n d B h u t a n knowledge, it is the first study to show population-level associations between stunting and development in several domains across a wide diversity of countries and cultures. The Young Lives Project, a set of large cohort studies of the effects of poverty on children in Ethiopia, India, Peru and Vietnam, has published on the detrimental effects of stunting on cognitive development in each of these settings (7,31) ; however, it has not as yet published pooled results or examined non-cognitive developmental domains. Casale and colleagues' large longitudinal 'Birth to 20' cohort study in South Africa found that early stunting was strongly associated with cognitive functioning at ages 4 and 5 years but did not predict 'social competence' (32) .…”

Childhood growth, schooling, and cognitive development: further evidence from the Young Lives study

“…Recent studies suggest that catch-up growth is possible throughout early and late stages of childhood (3)(4)(5) and that catch-up in physical growth is often accompanied by catch-up in other important child development and schooling outcomes (6)(7)(8)(9)(10). However, most of these studies are limited to investigations of catch-up growth during early childhood, ie, ages #8 y, whereas evidence on the prevalence and consequences of growth faltering and catch-up growth in late childhood remains scarce.…”

Preschool attendance: a multilevel analysis of individual and community factors in 21 low and middle-income countries

“…Community stunting rate has an odd ratio of 0.56. As undernutrition is associated with poor cognitive development, late entry into school, fewer years of schooling and reduced productivity (Crookston et al, 2011), children living in communities with larger stunting rates are less likely to be attending preschool. The large negative association between community stunting and preschool attendance supports the argument that early childhood development dimensions (health, nutrition and education) are strongly inter-related.…”