Differential influences of early growth and social factors on young children's cognitive performance in four low-and-middle-income birth cohorts (Brazil, Guatemala, Philippines, and South Africa)

Abstract

Background Studies relating childhood cognitive development to poor linear growth seldom take adequate account of social conditions related to both, leading to a focus on nutrition interventions. We aimed to assess the roles of both biological and social conditions in determining early childhood cognition, mediated by birthweight and early linear growth. Methods After exploratory structural equation modelling to identify determining factors, we tested direct and indirect paths to cognitive performance through birthweight and child height-for-age at 2 years, assessed between 4 and 8.5 years of age among 2448 children in four birth cohort studies in low-and-middle-income countries (Brazil, Guatemala, Philippines and South Africa). Determinants were compared across the cohorts. Findings Three factors yielded excellent fit, comprising birth endowment (primarily maternal age and birth order), household resources (crowding, dependency) and parental capacity (parental education). We estimated their strength together with maternal height in determining cognitive performance. Percentage shares of total effects of the four determinants show a marked transition from mainly biological determinants of birth weight (birth endowment 34%) and maternal height (30%) compared to household resources (25%) and parental capacity (11%), through largely economic determinants of height at 2 years (household resources (60%) to cognitive performance being predominantly determined by parental capacity (64%) followed by household resources (29%). The largely biological factor, birth endowment (maternal age and birth order) contributed only 7% to childhood cognitive performance and maternal height was insignificant. In summary, the combined share of social total effects (household resources and parental capacity) rises from 36∙2% on birth weight, to 78∙2% on height for age at 24 m, and 93∙4% on cognitive functioning. Interpretation Across four low- and middle-income contexts, cognition in childhood is influenced more by the parental capacity of families and their economic resources than by birth weight and early linear growth. Improving children's cognitive functioning requires multi-sectoral interventions to improve parental education and enhance their economic wellbeing, interventions that are known to improve also early childhood growth.

Maternal Shared Pleasure, Infant Withdrawal, and Developmental Outcomes in a High Risk Setting in South Africa

“…Shared pleasure requires a synchronous and joyful engagement which enhances the shared experience and thereby creates an opportunity for learning which may ultimately support infant cognitive development. As other studies have proposed, a significant positive quality of the mother infant relationship and parenting capacity has potential to contribute to favourable child development attachment ( 6 , 87 ) and SP in this case, may likely be one of those protective contributors.…”

Early-life stature, preschool cognitive development, schooling attainment, and cognitive functioning in adulthood: a prospective study in four birth cohorts

“…For Guatemala, we first standardised the test results obtained within each year of age and used the standardised values for the administration closest to age 7 years. 12 These harmonised scores permit analysis within each site but do not reference any external norm.…”

“…For example, in one study, parental capacity (measured by parental education and child dependency ratio) and resources explained more variance in childhood IQ than did birthweight and early height, and birthweight was a better predictor of early height than was parental capacity. 12 Although some nutritional interventions aimed at improving growth have also improved cognitive outcomes (albeit with small effect sizes), the effects of cognitive interventions in these same studies have been up to five times larger. 9 Furthermore, schooling has been shown to moderate the effects of poverty on cognitive development and academic achievement.…”

“…In low-income and middle-income countries (LMICs), greater emphasis has been placed on interventions to improve growth rather than social determinants of cognitive development. 12,16 Although nutrition is necessary for the developing brain 17 and stunting is an important population-level marker of healthy development, it is important to disentangle the relative specific contributions of stature, early IQ, and cognitive interventions, in this case schooling, on later cognitive ability.…”

The Shared Pleasure Paradigm: A study in an observational birth cohort in South Africa

“…Substantial numbers of perinatal mental health disorders occur in LMICs, particularly in poorer peri-urban and rural areas (Fisher et al 2012 ; Brittain et al 2015 ). The early social environment fundamentally determines early child development and influences long-term child health outcomes (Maggi et al 2010 ; Richter et al 2020 ). Risk factors such as socio-economic stressors, poor social support and substance use, perinatal mental health disorders may impact and undermine mothers’ capacity to respond optimally to infants’ needs (WHO 2018 ).…”