Blood pressure, memory and dementia…what’s the link?

Blood Pressure UK recently talked with Professor John Potter, Foundation Chair in Ageing & Stroke Medicine at the University of East Anglia, to take a closer look at the link between blood pressure, memory loss and dementia, and whether lowering blood pressure can help…

What do you mean by memory problems?

Memory problems become more common as we get older and can often be regarded as part of the natural ageing process. However, memory loss can progress to “mild cognitive impairment (MCI)” where individuals regularly mislay items or forget names or places. While these symptoms suggest short term memory issues, they do not significantly interfere with everyday life.

What is dementia?

Dementia is a diagnosis that can be linked with confusion, memory, communication loss and personality changes. Symptoms progress over time, causing a meaningful change to everyday life.

What are the different types of dementia?

There are two main types: Alzheimer’s disease and vascular cognitive impairment.

Around 60% of cases are due to Alzheimer’s disease and 15-20% are due to vascular cognitive impairment, or a mixture of both.

  • Alzheimer’s is linked to a build-up of abnormal proteins in the brain which result in the formation of ‘neurofibrillary tangles’ and ‘neurodegeneration’.
  • Vascular cognitive impairment can involve varying types of damage to the blood vessels including low blood flow in the brain, multiple small brain infarcts (where the blood supply is cut off to part of the brain) and the result of stroke in a specific area of the brain.

It is sometimes difficult to diagnose the underlying type of dementia but vascular cognitive impairment tends to be associated more with decision making and problem-solving issues and less with memory loss.

Is high blood pressure a risk for dementia?

Recent data suggest there is an increasing role for high blood pressure and other cardiovascular risk factors in the development of both types of dementia.

Many studies have shown that having a higher systolic blood pressure (the top number) in mid-life leads to a decline in cognition later on. It also increases the likelihood of mild cognitive impairment progressing to dementia, though high blood pressure doesn’t necessarily predict the rate of cognitive decline.

The effect of high blood pressure in later life on vascular cognitive impairment is inconsistent but may depend on ethnicity, with the Black and Hispanic populations appearing at higher risks than the White and Asian population. For the over 80s, higher blood pressure of over 130/85mmHg is actually linked with better cognitive function, although the number of studies is small.

Do blood pressure medicines help?

As high blood pressure is a major risk factor for cognitive impairment in most age groups, it can be expected that drug treatment to lower blood pressure should slow or stop such changes.

There are now several large clinical trials of blood pressure medicines and cognition and some, but not all, suggest that blood pressure treatment lowers the risk of dementia.

In summary, there is now convincing evidence that high blood pressure is related to both vascular dementia and Alzheimer’s along with milder forms of cognitive impairment – although in over 80s high blood pressure levels potentially reduce this risk.

Blood pressure medicines in those aged up to 80 at least reduces this threat, and the most important strategy is to achieve good blood pressure control and reduce other risk factors for diseases of the heart and blood vessels with a healthy lifestyle and making small changes today (such as reducing your salt intake) that can prevent future issues.