Socioeconomic and nutritional determinants outweigh gut microbiota influence on neurodevelopment in young children from Antananarivo, Madagascar

In 2024, stunted child growth affected 150 million children under the age of five years, underscoring its critical impact on global health. Stunting has also been associated with neurodevelopmental delays. This study explores the relationship between stunting, the fecal microbiota, and neurodevelopment in 2-5-year-old children from the Afribiota cross-sectional study in Madagascar. Children were assessed using the Ages and Stages Questionnaire (ASQ-3), covering five developmental domains (communication, personal-social, problem-solving, fine and gross motor). Fecal samples were analyzed via 16S rRNA gene amplicon sequencing. Classical bi- and multivariate analysis was combined with Structural Equation Modelling to evaluate direct and indirect associations between different clinical factors, the microbiota and neurodevelopment. Our study shows that stunting and low socioeconomic status are consistently linked to poorer neurodevelopmental outcomes, while low branched-chain amino acids and hemoglobin levels are associated with stunting. Furthermore, a higher microbial diversity within individuals (α-diversity-specifically the Shannon index-) was directly linked to improved neurodevelopment scores in one of the tested models, while gut microbiota variation between individuals (β-diversity) was not associated with neurodevelopment. These findings support the hypothesis of neurodevelopment being primarily influenced by nutritional and social factors, with a more limited role for microbiota diversity.