Study links blood pressure variability to greater risk of cognitive decline

Jul 20, 2021
High blood pressure affects about one in three Australians. Source: Getty

High blood pressure (hypertension) is a common condition, affecting about one in three Australians. While it’s common knowledge that persistent high blood pressure can increase your risk of a number of serious and potentially life-threatening health conditions, such as dementia, new data has suggested that more granular short- and long-term fluctuations in blood pressure are also an indicator of cognitive decline.

The study, published in the Journal of the American Heart Association, revealed high blood pressure variability (BPV) in older adults, particularly in men, is associated with an increased risk of dementia and cognitive decline.

“By around 2050, we believe that people aged 60 years and older will outnumber adolescents and youths,” Associate Professor Joanne Ryan, who co-led the study, said. “As an age‐related disease, and one with a notable lack of treatments, dementia will indefinitely remain a major public health priority. Any opportunity to identify early those at risk, and engage people in preventive therapies, is important.”

The study’s authors went on to say that while hypertension has previously been shown to be a strong predictor of dementia in later life, most studies investigating BPV involved younger people, older people already diagnosed with cognitive impairment, or used a single cognitive assessment tool to gauge cognitive acuity. So, for the study, rather than just a single cognitive assessment tool, participants underwent a series of cognitive tests.

“This enabled us to capture detail on many facets of cognition and memory, including global cognition, delayed episodic memory, verbal fluency, and processing speed and attention,” Ryan said. “They also underwent a validated depression scale prior to each annual cognitive test, which is important because depression may have an impact on cognitive function.”

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

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

Ryan said further studies are needed to help determine the underlying reasons for the sex-specific differences, and whether reducing BPV can preserve late-life cognitive function.

“While we don’t know for sure, it is tempting to speculate about the existence of different pathways towards cognitive decline in men and women,” she said. “Or sex hormones such as oestrogen across a woman’s lifetime may have a protective effect for women.

“More study is warranted into this area to help determine the underlying reasons for these sex-specific differences, and into research to find out whether reducing BPV can preserve late-life cognitive function.”

IMPORTANT LEGAL INFO This article is of a general nature and FYI only, because it doesn’t take into account your personal health requirements or existing medical conditions. That means it’s not personalised health advice and shouldn’t be relied upon as if it is. Before making a health-related decision, you should work out if the info is appropriate for your situation and get professional medical advice.

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