Access to quality health resources and environmental toxins affect the relationship between brain structure and BMI in a sample of pre and early adolescents

BACKGROUND: Environmental resources are related to childhood obesity risk and altered brain development, but whether these relationships are stable or if they have sustained impact is unknown. Here, we utilized a multidimensional index of childhood neighborhood conditions to compare the influence of various social and environmental disparities (SED) on body mass index (BMI)-brain relationships over a 2-year period in early adolescence. METHODS: Data were gathered the Adolescent Brain Cognitive Development Study(®) (n = 2,970, 49.8% female, 69.1% White, no siblings). Structure magnetic resonance imaging (sMRI), anthropometrics, and demographic information were collected at baseline (9/10-years-old) and the 2-year-follow-up (11/12-years-old). Region of interest (ROIs; 68 cortical, 18 subcortical) estimates of cortical thickness and subcortical volume were extracted from sMRI T(1)w images using the Desikan atlas. Residential addresses at baseline were used to obtain geocoded estimates of SEDs from 3 domains of childhood opportunity index (COI): healthy environment (COI(HE)), social/economic (COI(SE)), and education (COI(ED)). Nested, random-effects mixed models were conducted to evaluate relationships of BMI with (1) ROI (*) COI([domain]) and (2) ROI (*) COI([domain]) (*) Time. Models controlled for sex, race, ethnicity, puberty, and the other two COI domains of non-interest, allowing us to estimate the unique variance explained by each domain and its interaction with ROI and time. RESULTS: Youth living in areas with lower COI(SE) and COI(ED) scores were heavier at the 2-year follow-up than baseline and exhibited greater thinning in the bilateral occipital cortex between visits. Lower COI(SE) scores corresponded with larger volume of the bilateral caudate and greater BMI at the 2-year follow-up. COI(HE) scores showed the greatest associations (n = 20 ROIs) with brain-BMI relationships: youth living in areas with lower COI(HE) had thinner cortices in prefrontal regions and larger volumes of the left pallidum and Ventral DC. Time did not moderate the COI(HE) x ROI interaction for any brain region during the examined 2-year period. Findings were independent of family income (i.e., income-to-needs). CONCLUSION: Collectively our findings demonstrate that neighborhood SEDs for health-promoting resources play a particularly important role in moderating relationships between brain and BMI in early adolescence regardless of family-level financial resources.