BP variability an independent risk factor for dementia, Alzheimer’s
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BP may be an independent risk factor for the development of dementia, Alzheimer’s disease and vascular dementia, according to research published in Hypertension.
Researchers identified 7,844,814 participants from the Korean national health insurance system cohort without a history of dementia who underwent at least three health examinations between 2005 and 2012. Participants were stratified into quartiles by systolic and diastolic BP variability.
In a multivariable-adjusted model, researchers observed that, compared with those in the lowest three quartiles, risk for all-cause dementia was 6% higher for those in the highest quartile of diastolic BP variability (adjusted HR = 1.06; 95% CI, 1.04-1.07) and about 9% higher for those in the highest quartile of systolic BP variability (aHR = 1.09; 95% CI, 1.08-1.11).
In addition, participants who were in the highest quartile for both systolic and diastolic BP variability experienced an approximately 18% greater risk for all-cause dementia (aHR = 1.18; 95% CI, 1.16-1.19) compared with those who were in the lowest three quartiles for both.
Results were similar for Alzheimer’s disease and vascular dementia.
“We confirmed that higher visit-to-visit BP variability is associated with the incidence of all-cause dementia, Alzheimer’s disease and vascular dementia,” Jung Eun Yoo, of the department of family medicine of the Healthcare System Gangnam Center at Seoul National University Hospital, South Korea, and colleagues wrote. “In addition, in a novel result, we found that having both higher systolic BP variability and diastolic BP variability additively increased the risk of dementia and its subtypes in a general population.
“While the exact mechanism remains unclear, possible explanations have been suggested. First, marked fluctuations in BP and inconsistent perfusion result in repeated episodes of tissue hypoxia-ischemia,” the researchers wrote. “This oligemia can lead to brain amyloidogenesis by enhancing expression and processing of amyloid-beta peptide precursor protein, activating microglia, impairing neuronal protein synthesis, and causing neuronal damage and cellular death. In particular, these changes occur in the most vulnerable areas such as the hippocampi, which are among the sites to be affected earlier stage in Alzheimer’s disease.”
For this cohort population (mean age, 56 years; 53% men; 20% current smokers; 13% with diabetes), researchers excluded individuals younger than 40 years and had a history of all-cause dementia at baseline.
“These findings suggest that BP variability is an important risk factor, not only in patients with dementia, but also in general populations,” the researchers wrote. “Further research is warranted to examine whether reducing variability of blood pressure parameters decreases adverse outcomes.” – by Scott Buzby
Disclosures: The authors report no relevant financial disclosures.
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