Maternal and Childhood Weight and Brain Structure in Children: Separate and Combined Associations in a Cross‐Sectional Study

ABSTRACT Objective While prior work has related pregravid or childhood excess weight to brain outcomes in children, their combined associations remain unclear. We examined these relationships in 6‐year‐old children. Methods Ninety‐nine mother–child pairs (60% girls) were classified into four groups based on pregravid BMI (< 25 vs. ≥ 25 kg/m 2 ) and child BMI (< 85th and ≥ 85th percentile). T1‐weighted MRI assessed cortical thickness, sulcal depth, gyrification, and subcortical volumes in children. ANCOVA revealed group differences controlling age, sex, parental education, and birth weight (and total intracranial volume in non‐thickness models). Bonferroni‐adjusted post hoc tests followed omnibus tests. Results High pregravid BMI was associated with a thicker right superior temporal gyrus, while high child BMI was linked to greater gyrification in temporo‐cingulate cortices. Both maternal and child higher BMI were related to a thinner right cuneus and a smaller right accumbens and pallidum. Children with higher BMI born to mothers with higher BMI showed deeper sulci in the left caudal middle frontal gyrus and reduced gyrification in the left entorhinal cortex. Conclusions Higher BMI in both children and mothers, separately and jointly, was associated with gray matter differences in obesity‐related regions. Longitudinal studies are needed to establish temporal relationships, mechanisms, biomarkers, and functional implications.