Association of Circulating Biomarkers with Growth and Cognitive Development in Rural Tanzania: A Secondary Analysis of the Early Life Interventions in Childhood Growth and Development In Tanzania (ELICIT) Study.

Background: Children in low-resource areas experience nutritional and infection challenges delaying growth and cognitive development.

Objectives: Our goal was to assess for associations of circulating biomarkers related to nutrition and inflammation, with growth and developmental outcomes among children in a birth cohort in a resource-poor area in rural Tanzania.

Methods: We assessed data from 1,120 children participating in the Early Life Interventions for Childhood Growth and Development in Tanzania (ELICIT) study. At age 12 and 18 mo, participants had blood tests performed for hemoglobin, collagen-X, insulin-like growth factor-1 (IGF-1), fibroblast growth factor-21 (FGF21), thyroglobulin, ferritin, soluble transferrin receptor (sTFR), retinol binding protein-4 (RBP4), C-reactive protein (CRP), α1-acid glycoprotein (AGP), and CD14. At 18 mo, participants had anthropometry measured and converted to z-scores for length-for-age (LAZ), weight-for-age (WAZ) and head-circumference-for-age (HCZ) and had the Malawi Developmental Assessment Tool (MDAT) performed to evaluate cognitive development. We performed linear regression assessing biomarkers (predictor variable) on anthropometry and MDAT scores (dependent variables), adjusted for sex, socioeconomic status, and baseline values.

Results: There was a high degree of intrafactor correlation between 12 and 18 mo and interfactor correlation between biomarkers. IGF-1 and sTFR were positively and FGF21 and ferritin negatively associated with LAZ at 18 mo, whereas collagen-X and CD14 were additionally associated with recent linear growth. Only markers predominantly related to nutrition were consistently linked with WAZ at 18 mo, while RBP4 and AGP were additionally associated with recent change in WAZ. IGF-1 was positively and thyroglobulin, RBP4, and CD14 negatively linked to MDAT scores. IGF-1 was the only factor linked to both 18-mo LAZ and MDAT.

Conclusions: Individual biomarkers were consistently linked to growth and cognitive outcomes, providing support for relationships between nutrition and inflammation in early child development. Further research is needed to assess overlaps in how biomarker-related processes interact with both growth and learning. REGISTERED AT CLINICALTRIALS.GOV: NCT03268902.