Associations of Blood Pressure Level and Variability with Cortical Thickness: A Cross-Sectional Analysis from The Maracaibo Aging Study.

Abstract

Background: Although high blood pressure (BP) level and variability are associated with Alzheimer's Disease (AD), their relationship with cortical thickness in brain regions that are associated with AD is unclear. Furthermore, the role of 24-hour BP has not been examined. We investigated the associations of office and ambulatory BP measures with cortical thickness in brain regions implicated in AD.

Methods: We performed a cross sectional analysis of 304 participants without dementia from a population-based study with office and 24-hour BP and magnetic resonance imaging (MRI) data. We considered cortical thickness values derived from 10 regions throughout the frontal, parietal, and temporal lobes, and posterior cingulate cortex that are associated with risk and progression of AD. The association between BP and cortical thickness was tested using adjusted linear regression models.

Results: The mean age was 58.1y and 231 (76%) were women. Higher office systolic BP was associated with thinner temporal (β=-0.059; 95% confidence interval [CI], -0.112,-0.005) and posterior cingulate cortex (β=-0.095; 95% CI, -0.145,-0.045). 24-hour and nighttime BP levels were associated with thinner seven regions, with β-estimates ranging from 0.103 (95% CI, -0.182,-0.012) to -0.045 (95% CI, -0.080,-0.010). A higher 24-hour BP variability was associated with thinner middle frontal (β=-0.156; 95% CI, -0.282,-0.030) and middle temporal (β=-0.146; 95% CI, -0.268,-0.024) gyri, and posterior cingulate cortex (β=0.134; 95% CI, 0.026,-0.009).

Conclusions: Increased ambulatory BP level and variability are associated with cortical thinning in regions associated with AD. Better BP evaluation with out-of-office approaches might reduce brain structural changes associated with AD.