Abdominal obesity and lower gray matter volume: a Mendelian randomization study

Area of Science:

• Neuroscience
• Gerontology
• Public Health

Background:

• Obesity is a growing public health concern associated with various chronic diseases.
• Brain aging encompasses structural and volumetric changes that can impact cognitive function.
• Understanding the link between obesity and brain aging is crucial for preventative strategies.

Purpose of the Study:

• To investigate the association between anthropometric obesity markers and neuroimaging markers of brain aging.
• To examine the potential causal relationship between obesity markers and brain aging using Mendelian randomization.

Main Methods:

• Cross-sectional analysis of 1779 individuals from the 3C-Dijon cohort.
• Quantitative magnetic resonance imaging (MRI) to assess brain volume, gray matter volume (GMV), white matter hyperintensity volume (WMHV), and brain infarcts.
• Mendelian randomization (MR) analysis to infer causality.

Main Results:

• Larger waist-to-hip ratio (WHR) and waist circumference (WC) were significantly associated with lower total brain volume (TBV) and GMV, independent of BMI and vascular risk factors.
• Higher BMI, WC, and WHR were linked to increased WMHV, and WC to brain infarcts.
• MR analysis in women suggested a causal inverse association between WHR and GMV.

Conclusions:

• Anthropometric measures of obesity, particularly central obesity (WC, WHR), are associated with brain aging markers.
• These findings suggest a potential causal role of central obesity in brain structural changes.
• Further research is needed to confirm causal links and explore intervention strategies.