What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Alzheimer's disease biomarkers (n=54). Intervention: Elevated short-term blood pressure variability vs. Lower blood pressure variability. Primary outcome: Plasma Aβ1–42 levels (standardized ß = -0.36, 95% CI -0.61, -0.12, p=0.005).

October 13, 2022Open Access

Blood pressure variability and plasma Alzheimer’s disease biomarkers in older adults

Key Result

Elevated short-term blood pressure variability over 5 minutes was significantly associated with lower levels of plasma Aβ1–42 (standardized ß = -0.36) and higher levels of total tau.

Study Design

Type

Cross-Sectional (n=54)

Multicenter

Yes

Structured PICO

Does elevated short-term blood pressure variability associate with plasma Alzheimer's disease biomarkers in community-dwelling older adults?

Population

54 community-dwelling older adults aged 55-88 without major neurocognitive impairment, assessed cross-sectionally for short-term blood pressure variability and plasma Alzheimer's disease biomarkers.

Exposure

Elevated short-term blood pressure variability (BPV) measured continuously over a 5-minute resting period

Outcome

Plasma Alzheimer's disease biomarkers (Aβ1–42, Aβ1–40, Ptau181, total tau, and their ratios)surrogate

Elevated short-term blood pressure variability is associated with plasma biomarkers of increased Alzheimer's disease pathophysiology in community-dwelling older adults, independent of average blood pressure levels.

Main Result

Effect estimate: standardized ß = -0.36 (95% CI -0.61, -0.12)

p-value: p=0.005

Limitations

Relatively small sample size
Inability to assess potential antihypertensive medication class effects
BP measurements and plasma samples were collected at two sites, which could introduce measurement error
Inability to control for all factors causing BP fluctuations (e.g., stimulant intake, medication use, pain, perceived stress)
Cross-sectional nature limits the ability to assess directionality or potential mechanisms

Abstract

Abstract Blood pressure variability is an emerging risk factor for Alzheimer’s disease in older adults, independent of average blood pressure levels. Growing evidence suggests increased blood pressure variability is linked to Alzheimer’s disease pathophysiology indexed by cerebrospinal fluid and positron emission tomography markers, but relationships with plasma Alzheimer’s disease markers have not been investigated. In this cross-sectional study of 54 community-dwelling older adults (aged 55–88, mean age 69.9 8.2 SD), elevated blood pressure variability over 5 min was associated with lower levels of plasma Aβ 1–42 (standardized ß = − 0.36 95% CI − 0.61, − 0.12; p = 0.005; adjusted R 2 = 0.28) and Aβ 1–42 : Aβ 1–40 ratio (ß = − 0.49 95% CI − 0.71, − 0.22; p < 0.001; adjusted R 2 = 0.28), and higher levels of total tau (ß = 0.27 95% CI 0.01, 0.54; p = 0.04; adjusted R 2 = 0.19) and Ptau 181 :Aβ 1–42 ratio (ß = 0.26 95% CI 0.02, 0.51; p = 0.04; adjusted R 2 = 0.22). Findings suggest higher blood pressure variability is linked to plasma biomarkers of increased Alzheimer’s disease pathophysiology.

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