Variation in blood pressure is associated with white matter microstructure but not cognition in African Americans

Area of Science:

• Neuroscience
• Cardiovascular Health
• Medical Imaging

Background:

• Hypertension is a significant risk factor for cerebrovascular disease (CVD), particularly prevalent in African Americans.
• Limited understanding exists regarding blood pressure (BP) effects on brain-behavior in this demographic.
• High BP is associated with white matter and executive function changes in Caucasian populations.

Purpose of the Study:

• To investigate the associations among BP, brain structure (white matter integrity), and neuropsychological functioning in African Americans without a history of CVD.
• To examine how BP influences specific neural regions and cognitive functions in this population.

Main Methods:

• Diffusion tensor imaging (DTI) was used to assess white matter integrity via fractional anisotropy (FA) in specific brain regions (genu and splenium of the corpus callosum, whole brain).
• A neuropsychological battery measured executive function and memory composite scores.
• Mean arterial blood pressure (MABP) was characterized and analyzed in relation to FA and cognitive scores, considering BP medication status.

Main Results:

• Higher MABP was associated with lower FA in the genu of the corpus callosum and a trend for whole-brain FA, after controlling for age.
• This relationship between MABP and FA was significant only in the nonmedicated subgroup.
• No significant associations were found between MABP or FA and the neuropsychological composite scores, irrespective of medication use.

Conclusions:

• Variations in BP may contribute to alterations in white matter integrity within specific neural regions.
• These findings are particularly relevant for nonmedicated individuals without symptomatic CVD.
• The study highlights the potential impact of BP on brain structure in African Americans, even in the absence of diagnosed cerebrovascular disease.