Sex dimorphism in gray/white matter volume and diffusion tensor during normal aging

Area of Science:

• Neuroimaging
• Radiology
• Gerontology

Background:

• Normal brain aging involves changes in gray/white matter volume and white matter microstructure.
• Diffusion MRI metrics like mean diffusivity (MD) and fractional anisotropy (FA) are sensitive to microstructural alterations.
• Understanding sex differences in brain aging is crucial for personalized health strategies.

Purpose of the Study:

• To investigate sex-specific differences in global and regional brain volume, MD, and FA during normal aging.
• To identify age-related changes and their modulation by sex using voxel-based analysis.

Main Methods:

• Voxel-based morphometry and diffusion tensor imaging were used.
• 245 healthy subjects (115 women, 130 men) aged 21-71 years were analyzed.
• Statistical analyses included global and regional assessments with age and sex as factors.

Main Results:

• Global white matter fraction and MD showed quadratic age effects. Both sexes exhibited anterior gray matter volume loss, anterior white matter FA decrease, and periventricular/perisylvian MD increase with age.
• Men showed a steeper decline in FA in right inferior fronto-temporal areas and accelerated MD increase in frontal, temporal, and parietal regions compared to women.
• No significant age-sex interaction was found for regional volume, nor accelerated decline/increase for women.

Conclusions:

• Significant sex dimorphism exists in global and focal brain aging patterns, particularly in white matter microstructure.
• Men exhibit accelerated microstructural aging in specific white matter tracts compared to women.
• These findings contribute to understanding sex-specific neurodegenerative processes and inform targeted interventions.