Long-Term Blood Pressure Variability, Hippocampal Subfield Volume and Cognitive Decline: A Population-Based...

Area of Science:

• Neurology
• Neuroimaging
• Cardiovascular Research

Background:

• Long-term blood pressure variability (BPV) is a known risk factor for cognitive decline.
• The precise mechanisms linking BPV to cognitive impairment remain incompletely understood.
• Investigating the impact of BPV on specific brain structures like the hippocampus is crucial.

Purpose of the Study:

• To examine the relationship between long-term BPV and the volume of specific hippocampal subfields.
• To assess the association between BPV and overall cognitive function.
• To determine if hippocampal subfield volume mediates the impact of BPV on cognition.

Main Methods:

• A prospective study involving 1,366 adults with at least three survey visits between 2006 and 2020.
• Blood pressure variability (BPV) was calculated as the standard deviation of manual blood pressure readings.
• Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA); brain MRI was used to segment 12 hippocampal subfields.

Main Results:

• Elevated systolic BPV (SBPV) correlated with reduced volumes in hippocampal subfields CA1, CA2-3, molecular layer, and HATA.
• Elevated diastolic BPV (DBPV) was associated with a smaller molecular layer volume.
• Both SBPV and DBPV were negatively associated with MoCA scores, indicating poorer cognitive function. The molecular layer volume mediated 9.45% of the association between SBPV and cognitive scores.

Conclusions:

• Increased blood pressure variability is associated with atrophy in specific hippocampal subfields.
• BPV contributes to cognitive decline, with the molecular layer volume playing a mediating role in the SBPV-cognition relationship.