Characterizing the relationship between functional network dynamics and the body mass index

Background: Obesity has increasingly been linked to alterations in brain functional network organization. While static functional connectivity studies have revealed important associations with body mass index (BMI), the role of dynamic functional network properties and their topological variability remains largely unexplored. This study aimed to investigate the relationship between BMI and the dynamics of brain functional network connectivity. Methods: Resting-state fMRI data from 776 healthy young adults were analyzed using independent component analysis to extract independent components (ICs) and a sliding-window approach to derive dynamic brain connectivity metrics. Four recurring whole-brain functional connectivity states were identified, and the temporal variability of topological properties was calculated. We examined the relationships between BMI and the temporal properties of FC states, and between BMI and the temporal variability of topological properties. Results: In the whole-brain level, BMI was positively correlated with the fractional window and mean dwell time of one FC state, which was characterized by strong intra-network and inter-network connectivity of the visual network (VN). In the regional level, significant negative correlations were found between BMI and the temporal variability of nodal efficiency and local efficiency in ICs belonging to the VN. Conclusion: Our findings suggest modest, statistically significant associations between BMI and whole-brain functional network dynamics, with VN-dominant connectivity patterns emerging as candidate correlates of higher BMI.