Pulse pressure is associated with Alzheimer biomarkers in cognitively normal older adults

Abstract

Objective: The current study examined the association between pulse pressure (PP) and CSFbased biomarkers for Alzheimer disease, including β-amyloid 1-42 (Aβ1-42 and phosphorylated tau (P-tau) protein, in cognitively normal older adults. Methods: One hundred seventy-seven cognitively normal, stroke-free older adult participants (aged 55-100 years) underwent blood pressure assessment for determination of PP (systolic 2 diastolic blood pressure) and lumbar puncture for measurement of CSF Aβ1-42 and P-tau. Pearson correlations and multiple linear regression, controlling for age, sex, APOE genotype, and body mass index, evaluated the relationship between PP and Alzheimer disease biomarkers. Results: PP elevation was associated with increased P-tau (r=0.23, p=0.002), reduced Aβ1-42 (r=-0.19, p=0.01), and increased P-tau to Aβ1-42 ratio (r=0.27, p<0.001). After controlling for covariates, PP remained associated with P-tau (β=0.18, p=0.0196) and P-tau to Aβ1-42 ratio (β=0.0016, p<0.001) but was no longer associated with Aβ1-42 (β=20.1, p=0.35). Post hoc multivariate analyses indicated that increased PP was associated with all biomarkers in younger participants (aged 55-70 years) (Aβ1-42: p=0.050; P-tau: p=0.003; P-tau to Aβ ratio: p=0.0007) but not older participants (aged 70-100 years). Conclusions: PP elevation is associated with increased CSF P-tau and decreased Aβ1-42 in cognitively normal older adults, suggesting that pulsatile hemodynamicsmay be related to amyloidosis and tau-related neurodegeneration. The relationship between PP and CSF biomarkers is age-dependent and observed only in participants in the fifth and sixth decades of life. © 2013 American Academy of Neurology.