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

Abstract

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.

Grey matter alterations in obesity: A meta‐analysis of whole‐brain studies

“…Additionally, we also found some clusters with increased GMV in patients with obesity, with the largest cluster being in the cuneus. This effect of increased GMV has not been found in the reviews including nonpatient samples . While we do not have a clear‐cut explanation for this observation, the literature suggests higher activation in this region, and parts of the occipital cortex, to disorder‐specific stimuli in anxiety disorder patients .…”

“…No increased GMV was found with increased levels of obesity‐related variables (like BMI and body waist circumference). A second review was posted on the open‐access preprint server BioRxiv (without peer‐review), in which 23 papers were included. The papers also investigated the correlation between BMI and GMV; therefore, the main proportion of the papers (74%) is the same as in the published review .…”

“…In this review, we will focus on studies including patients with obesity as the main diagnosis compared with lean individuals in between‐group comparisons. Studies that use a dimensional approach in healthy controls correlating BMI with GM density reflect in our opinion different aspects and have already been described elsewhere . With regard to structural abnormalities, we will focus on voxel‐based morphometry (VBM) studies, the most frequently used type of morphometric measurements of brain anatomy at the moment.…”

A systematic review of diffusion tensor imaging studies in obesity

“…5 Previous meta-analyses on GM alterations in obesity suggest that degeneration in these brain regions may underlie impaired internal feedback within the circuits associated with reward, emotion, and impulse control and, therefore, contribute to weight gain. [12][13][14] In contrast to the cerebral cortex, the role of white matter (WM) has gained significant recognition only recently. Overall, compared with existing studies on obesity-related GM changes, there is less evidence for a comparable association with WM changes.…”

A systematic review of diffusion tensor imaging studies in obesity

“…These brain areas have been previously associated with reward, emotion processing, memory and motivation, as well as impulse control and decision-making 9 . Previous meta-analyses on GM alterations in obesity suggest that degeneration in these brain regions may underlie impaired internal feedback within the circuits associated with reward, emotion, and impulse control and, therefore, contribute to weight gain [10][11][12] .…”