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Variability in blood pressure associated with increased risk of dementia, especially in men



A new report from the long-term ASPREE study, involving Monash University, found that variability in high blood pressure (BPV) in the elderly, especially in men, is associated with an increased risk of dementia and cognitive decline.

Published in the Journal of the American Heart Association, the findings may identify those at increased risk for major cognitive impairment, allowing triage into increased surveillance, and pave the way for new areas of research.

The new article is one of many important health findings from the ASPREE (ASPirin in Reducing Events in the Elderly) dataset. The Aspirin Primary Prevention Trial released the world’s leading acclaimed results in 2018. Further analysis of comprehensive, high-quality data from 19,114 Australians and Americans continues to generate new findings in the elderly in good health, mainly over 70 years old.

This study was co-led by Associate Professor Joanne Ryan of the Monash School of Public Health and Preventive Medicine and Professor Mike Ernst of the University of Iowa.

“By 2050, we believe that people aged 60 and over will outnumber adolescents and young people. As an age-related disease and with a notable lack of treatment, dementia will remain a top public health priority indefinitely, ”said Associate Professor Ryan.

“Any possibility of early identification of people at risk and of involving people in preventive therapy is important. “

Hypertension – systemic high blood pressure – at mid-life has already been shown to be a strong predictor of dementia later in life. More recently, data has shown that more granular short- and long-term fluctuations in blood pressure (BPV) are also an indicator of cognitive decline.

However, most studies of BPV have involved younger people, older people previously diagnosed with cognitive impairment, or used a single cognitive assessment tool to assess cognitive acuity.

“The ASPREE dataset was uniquely suited to provide a robust answer to this question; a large cohort of participants underwent standardized blood pressure and cognition assessments, and they received long-term follow-up, ”says Associate Professor Ryan.

“It is important to note that, rather than a single cognitive assessment tool, participants underwent a series of cognitive tests. This allowed us to capture details on many facets of cognition and memory, including overall cognition, delayed episodic memory, verbal fluency, and processing speed and attention.

“They also underwent a validated depression scale before each annual cognitive test, which is important because depression can impact cognitive function.”

Blood pressure was recorded for all participants during their annual visits, according to American Heart Foundation guidelines.

Data from 16,758 participants were included in this study. The researchers grouped the participants at baseline (entry into the study) into three groups, based on BPV: low, medium, and high. BPV was generally higher in women than in men, but cognitive scores were similar in participants with low, medium, and high BPV.

Over time, differences have emerged. People in the highest BPV group were shown to have a significantly increased risk of incident dementia and cognitive decline compared to those in the lowest BPV group. Being male also significantly increased the risk.

The findings support earlier findings that suggested BPV may be a useful indicator of cognitive decline, expanding our understanding to include older, relatively healthy adults who had reached the end of life without significant cognitive impairment – a group which is generally not considered to be at high risk for dementia during their remaining lifespan.

The results also provide the first evidence for possible gender-specific effects of BPV on cognition.

The biological mechanisms underlying the relationship between BPV and cognitive decline remain unclear, and the researchers say this should be further investigated.

A growing body of evidence suggests that BPV is associated with structural changes in the brain, including increased damage in the brain called white matter hyperintensities, increased small bleeding in the brain, and enlarged fluid-filled spaces in the brain. brain matter. It is not known whether these changes are caused by BPV or vice versa.

The degeneration of neurons and synapses associated with Alzheimer’s disease can influence the body’s regulation of blood pressure, which may contribute to an increase in BPV. This can cause a loop, in which microvascular damage due to unstable blood pressure could alter the permeability of the blood-brain barrier, allowing accelerated damage to neurons in the brain. While all of the ASPREE participants had no symptoms of cognitive impairment upon entry into the study, some may have had established pre-symptomatic illness that contributed via this pathway.

Men have a higher lifetime risk than women of other known risk factors for cognitive decline, such as uncontrolled high blood pressure and smoking. But even when the researchers took these into account, the increased risk for men remained.

Associate Professor Ryan said: “While we don’t know for sure, it’s tempting to speculate that there are different pathways to cognitive decline in men and women. Or sex hormones such as estrogen throughout a woman’s life can have a protective effect for women.

“More studies are needed in this area to help determine the underlying reasons for these gender-specific differences, and in research to find out whether lowering BPV may preserve cognitive function at the end of life.”

Read the full article in the Journal of the American Heart Association titled: Long-term blood pressure variability and risk of cognitive decline and dementia in the elderly.
DOI: 10.1161 / JAHA.120.019613

About ASPREE (ASPirin for reducing events in the elderly)

ASPREE was the first multi-site clinical trial of low-dose aspirin for primary prevention in the elderly, conducted by Monash University in Australia and the Berman Center for Outcomes and Clinical Research in the United States. Key findings published in the New England Journal of Medicine in September 2018 were incorporated into the American College of Cardiology / American Heart Association guidelines for aspirin in March 2019. The follow-up observational study, ASPREE-XT (expansion) started in mid-2017 and continues today. .

Twitter: @aspree_org W: aspree.org

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