Reduced gray matter volume in the orbitofrontal cortex is associated with greater body mass index: a coordinate-based meta-analysis

Meta-analyses of neuroimaging studies have not found a clear relationship between the orbitofrontal cortex and obesity, despite animal and human studies suggesting the contrary. Our primary meta-analysis examined what regions are associated with reduced gray matter volume, given increased body mass index. We identified 23 voxel-based morphometry studies examining the association between gray matter volume and body mass index. In a sample of 6,788 participants, we found that greater body mass index is associated with decreased gray matter volume in the right Brodmanns’ area 10 and 11, forming part of the right orbitofrontal cortex (FWE, p=0.05). Use of Brodmanns’ areas 10 and 11 as seeds in a Neurosynth network coactivation and text decoding analysis revealed that these regions are associated with studies of emotional regulation and processing, clinical symptoms and disorder, ‘mentalizing’ and social cognition, and the Default mode network. Our finding uniquely contributes to the literature in showing a relationship between the orbitofrontal cortex and obesity and showing the wide-ranging impact these differences may have on social, mental, and emotional functioning as well as on the Default mode network. Exploratory analyses suggest the need for studies examining the effect of age on these findings.