The mediating role of brain structural-functional connectivity coupling in linking paternal education to BMI and depressive scores in young adults.

BACKGROUND: Parental education is associated with body mass index (BMI), mental health, and neurodevelopment in young adults, yet the neurobiological mechanisms remain unclear. This study investigated whether parental education is related to BMI and depressive scores through brain structural-functional connectivity (SC-FC) coupling. METHODS: This study included 490 healthy young adults who underwent resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) scans. Parental education was measured as years of schooling, BMI by weight/height2, and depressive scores by the Beck Depression Inventory-II (BDI). SC and FC were derived from DTI and rs-fMRI, respectively. SC-FC coupling was quantified using Spearman's correlation between SC and FC matrices. Associations among variables were examined using Pearson correlation and mediation analyses. RESULTS: Paternal education was significantly correlated with BMI (r = 0.10, P < 0.05) and depressive scores (r = -0.09, P < 0.05). Additionally, paternal education, BMI, and depressive scores were positively associated with SC-FC coupling in the right inferior parietal lobule (IPL, r = 0.19, corrected P < 0.001; r = 0.12, corrected P < 0.05; r = 0.10, corrected P < 0.05, respectively). Mediation analysis showed that the right IPL statistically mediated the associations of paternal education with both BMI (indirect effect = 0.01, 95% confidence interval (CI): 0.001-0.04) and depressive scores (indirect effect = 0.01, 95% CI: 0.001-0.03). CONCLUSION: In this cross-sectional study, paternal education was associated with BMI and depressive scores, with SC-FC coupling in the right IPL statistically mediating these associations. No corresponding effects were observed for maternal education. These findings suggest a potential neural pathway linking socioeconomic factors to physical and mental health outcomes. CLINICAL TRIAL NUMBER: Not applicable.