26.2 Low Family Income from Fetal Life Onward and Child Brain Morphology: Differential Impact by Ethnic Minority and Majority Status in a Population-Based Study

Poverty is a known determinant of child psychological and cognitive development; this association is possibly mediated by child brain morphology. However, no imaging study assessed poverty prospectively from pregnancy onward. Further, poverty and ethnic minority status often co-occur, but the association has not been examined by ethnicity. We aimed to investigate the association of low family income from fetal life onward with brain morphological differences. We used data from Generation R, a prospective population-based cohort in the Netherlands, and analyzed 2166 mother-child dyads. Low income, a measure of poverty, in pregnancy and in early childhood was defined based on the standardized household income and the national low-income threshold; 442 children were “ever exposed to low income.” Maternal national origin was defined as Dutch (n = 1365), Non-Dutch Western (n = 271), and Non-Western (n = 530). School performance was assessed by a national assessment. Child brain morphology was measured with brain structural MRI when children were 10 years old. Children ever exposed to low income had smaller amygdala volume (β = –0.11; 95% CI, –0.21 to –0.002), especially if exposed in pregnancy. Importantly, the association differed by national origin (p interaction total brain: 0.05; cortical gray matter: 0.04). Children from the non-Western minority group exposed to low income had smaller amygdala volumes than the minority controls, driving the overall results. In contrast, children from the Dutch majority group ever-exposed to low income had smaller total brain, cortical gray matter, and cerebral white matter volumes than Dutch controls, an association not observed in the minority group. Further, the differences in total brain volume mediated the association between poverty and school performance in Dutch-origin children. Exposure to low family income early in life was associated with brain morphological differences in children. Global brain volume differences among Dutch children of low-income households possibly reflect broad developmental disadvantages, resulting in poor academic performance. Among poor non-Western children, the smaller amygdala volumes suggest that response to stress including discrimination plays a specific role.