Neurodevelopmental Inequality arising from Early Childhood Stunting: Evidences from Brain Connectivity

Abstract

Early childhood stunting (ECS) affects millions of children globally and conjectured to result in suboptimal brain and cognitive development later in life. Charting out the trajectory of brain network development and most importantly how the compensation of function can be achieved gives windows of intervention to clinicians, educators and policy makers. In this study, advanced network neuroscience tools, graph theoretical methods applied on diffusion weighted MR-imaging (DWI) revealed the effects of ECS on white matter (WM) organization in a community-based birth cohort of 170 children (mean age = 9.18 years, SD = 0.28) from Vellore, India. Based on stunting status at ages two, five, and nine years, children were categorised into four groups: always stunted (AS; n=21), stunted until five with catch-up at nine (S5C9; n=31), stunted until two with catch-up at five (S2C5; n=28), and never stunted or typically developing (TD; n=90). The catch-up groups showed strikingly similar anthropometric measures compared to TD. However, all stunted groups (AS, S5C9, S2C5) showed significantly lower performance and verbal IQ scores compared to TD children. DWI data revealed AS children exhibited shorter tract lengths across select cortico-cortical connections, an increased number and strength of short- and medium-range connections, and a corresponding reduction in long-range connections and strength. Network analyses further revealed that AS and S5C9 groups displayed higher local clustering and local efficiency relative to TD, reflecting greater local segregation of brain networks. Hub-like modules was broadly conserved across groups, although both catch-up groups (S2C5 and S5C9) showed additional hubs, suggesting compensatory network reorganization via a more modular architecture. Together, these findings provide novel evidence that ECS is linked to altered structural reorganization of brain networks and reduced cognitive performance in later childhood. While persistent stunting (AS) is associated with the most pronounced alterations, partial catch-up (S2C5 and S5C9) is accompanied by compensatory adaptations, such as increased short-range connectivity and recruitment of additional hubs. These results underscore the critical importance of early nutritional interventions to support optimal brain network development.