Cardiovascular risk factors and APOE-ε4 status affect memory functioning in aging via changes to temporal stem...

Area of Science:

• Neuroscience
• Gerontology
• Medical Imaging

Background:

• Inconsistent findings link hypertension, obesity, and apolipoprotein E (APOE) genotype to memory performance in older adults.
• Previous studies may have overlooked the role of structural brain changes in mediating these associations.
• Understanding these relationships is vital for addressing age-related memory decline.

Purpose of the Study:

• To clarify the direct and indirect relationships between hypertension, obesity, APOE genotype, and memory performance in healthy older adults.
• To investigate the mediating role of temporal stem white matter integrity in these associations.
• To elucidate the complex interplay of risk factors and brain structure on cognitive function.

Main Methods:

• Path modeling analysis was employed to examine direct and indirect effects.
• 125 healthy older adults underwent neuropsychological assessment.
• Diffusion-weighted magnetic resonance imaging (MRI) was used to assess temporal stem white matter integrity.

Main Results:

• Hypertension and demographic factors (age, sex, education) showed direct effects on memory.
• Body mass index (BMI), hypertension, APOE-ε4 status, age, and sex indirectly affected memory via temporal stem white matter integrity.
• Sex had a dual effect: females performed better directly, but poorer with greater temporal stem white matter integrity.

Conclusions:

• Changes in temporal white matter integrity significantly mediate the impact of risk factors on memory performance in aging.
• Accounting for indirect effects via structural brain changes is essential for a comprehensive understanding of cognitive aging.
• This research highlights the importance of considering both direct and indirect pathways in cognitive health research.