Fluctuating blood pressure may be a hidden culprit in dementia risk for seniors

A new study by Australian researchers has shown that fluctuating blood pressure can increase the risk of dementia and vascular problems in older people.

Short blood pressure (BP) fluctuations within 24 hours and over several days or weeks are linked with impaired cognition, say University of South Australia (UniSA) researchers who led the study.

Study: Cross-sectional associations between short and mid-term blood pressure variability, cognition, and vascular stiffness in older adults. Image Credit: New Africa / Shutterstock

Higher systolic BP variations (the top number that measures the pressure in arteries when a heart beats) are also linked with stiffening of the arteries, associated with heart disease.

The findings have been published in Cerebral Circulation – Cognition and Behaviour journal.

Lead author Daria Gutteridge, a Ph.D. candidate based in UniSA's Cognitive Ageing and Impairment Neuroscience Laboratory (CAIN), says it's well-known that high blood pressure is a risk factor for dementia. Still, little attention is paid to fluctuating blood pressure.

"Clinical treatments focus on hypertension, while ignoring the variability of blood pressure," Gutteridge says.

"Blood pressure can fluctuate across different time frames – short and long – and this appears to heighten the risk of dementia and blood vessel health."

To help explore the mechanisms that link BP fluctuations with dementia, UniSA researchers recruited 70 healthy older adults aged 60-80 years with no signs of dementia or cognitive impairment.

Their blood pressure was monitored, they completed a cognitive test, and their arterial stiffness in the brain and arteries was measured using transcranial Doppler sonography and pulse wave analysis.

"We found that higher blood pressure variability within a day and across days was linked with reduced cognitive performance. We also found that higher blood pressure variations within the systolic BP were correlated with higher blood vessel stiffness in the arteries.

"These results indicate that the different types of BP variability likely reflect different underlying biological mechanisms, and that systolic and diastolic blood pressure variation are both important for cognitive functioning in older adults."

The researchers say the links were present in older adults without any clinically relevant cognitive impairment, meaning that BP variability could serve as an early clinical marker or treatment target for cognitive impairment.