Fluctuating blood pressure increases dementia risk: study

While high blood pressure (BP) is a known risk factor for dementia, new research suggests that fluctuating BP can also increase this risk in older people.

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

“Clinical treatments focus on hypertension, while ignoring the variability of blood pressure,” said lead author Daria Gutteridge, a PhD candidate based in UniSA’s Cognitive Ageing and Impairment Neuroscience Laboratory (CAIN).

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

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

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, as well as across days, was linked with reduced cognitive performance. We also found that higher blood pressure variations within the systolic BP were linked 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 links were present in older adults without any clinically relevant cognitive impairment, meaning that BP variability could potentially serve as an early clinical marker or treatment target for cognitive impairment, the researchers said.

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

Image credit: iStockphoto.com/Zinkevych