White matter integrity differences in obesity: A meta-analysis of diffusion tensor imaging studies

Area of Science:

• Neuroimaging
• Obesity Research
• Cognitive Neuroscience

Background:

• Diffusion Tensor Imaging (DTI) studies suggest a link between obesity and impaired white matter (WM) integrity, affecting cognitive function.
• Previous research on WM integrity changes in obesity has yielded inconsistent results.

Purpose of the Study:

• To systematically identify specific white matter tracts consistently altered in individuals with obesity.
• To investigate the association between obesity metrics and white matter integrity using Fractional Anisotropy (FA) and Mean Diffusivity.

Main Methods:

• Conducted a systematic literature search for studies correlating obesity measures with FA or Mean Diffusivity.
• Performed a meta-analysis of FA datasets using Anisotropic Effect Size-Signed Differential Mapping software.
• Validated findings with an independent Human Connectome Project dataset.

Main Results:

• Meta-analysis revealed a consistent association between increased obesity measurements and reduced FA in the genu of the corpus callosum.
• Validation analysis confirmed lower FA in the genu of the corpus callosum in individuals with obesity compared to normal-weight individuals (p = 0.028).

Conclusions:

• Obesity is associated with reduced white matter integrity in the genu of the corpus callosum.
• This brain region connects frontal areas critical for executive functions, suggesting a potential mechanism for cognitive impairment in obesity.
• Further research is warranted to elucidate the mechanisms underlying the link between obesity and white matter integrity loss.