Leveraging MRI Relaxometry to Examine Relationships Between the Area Deprivation Index and White Matter Myelination in Infants and Children

Background: Early life adversity (ELA) refers to exposure to negative experiences in childhood. Prior studies have related ELA to poorer physical health and neurodevelopmental outcomes, implicating ELA as a critical area of study. Existing neuroimaging and behavioral literature has established clear associations between ELA and neurodevelopment in adolescence and adulthood. Less understood is how ELA in infancy and early childhood relates to early measures of brain development.

Objectives: The Area Deprivation Index (ADI) is a neighborhood disadvantage measure that combines factors such as household income, housing conditions, and employment outcomes to quantify the adversity an individual faces based on their census-tract level location of residence. The present study aimed to quantify the relationship between ELA as quantified by the ADI and pediatric white matter myelination in a sample of infants and children aged 0-10 years old (n =43).

Design/Methods: White matter myelination was quantified in regions previously associated with ELA in adolescents and adults using longitudinal relaxation rates (R1) calculated from images acquired with the MPnRAGE magnetic resonance imaging acquisition protocol. The ADI was calculated based on participants’ primary address at the time of visit. A region-of-interest linear mixed effects analysis assessed for relationships between the ADI and R1, controlling for age and sex. A subsequent voxel-based analysis assessed these relationships across the white matter skeleton.

Results: Higher ADI scores (increased neighborhood disadvantage) were associated with lower R1 (lower myelin content) in white matter regions including the internal capsule, corona radiata, cingulate gyrus, fronto-occipital fasciculus, superior longitudinal fasciculus, uncinate fasciculus, and corpus callosum. A voxel-based analysis of the entire white matter skeleton revealed significant associations between the ADI and R1 in bilateral clusters across the white matter skeleton (Figure 1).

Conclusions: The implicated regions have been implicated in cognitive, emotional, and motor functions, suggesting a significant association between the ADI and pediatric white matter myelination in functionally relevant regions. Future work should explore which components of the ADI drive this relationship and if these neuroimaging findings relate to developmental outcomes. These analyses should also be replicated in a larger, nationally representative sample to corroborate these findings.