Heart-brain link: how heart disease increases the risk of dementia

Lead Investigator: Dr Sana Suri

• Institution: University of Oxford
• Grant type: Junior Fellowship
• Duration: 36 months
• Amount: £224,812.46

Why did we fund this research?

Comments from our Research Network volunteers:

‘The link between vascular factors and dementia is very important and I am pleased to see this proposal.’

Project summary

The heart-brain link is vital for supplying brain cells with energy and oxygen. Poor heart health or carrying the Alzheimer’s risk gene APOE4 can increase risk of dementia.

This study is testing whether poor heart health in midlife leads to a weaker heart-brain link in later life.

The background 

We know that what is good for the heart is good for the head. Research suggests that improving your heart health through diet and exercise can help to reduce risk of dementia.

Alzheimer’s disease and heart disease have many overlapping risk factors such as having poor heart health in mid-life and carrying the APOE4 risk gene.

Brain cells need a constant supply of blood and oxygen to work properly. Part of the role of the heart-brain link is to increase blood supply to the brain when it needs more energy and oxygen. This function is performed by the cerebrovascular reactivity (CVR).

Higher CVR is a good indicator of brain health while lower CVR can occur as a result of heart disease. Dr Suri suggests lower CVR may lead to dementia.

We know from Dr Sana Suri’s previous work that young adults who carry the APOE4 risk gene have a weaker CVR.

Brain imaging has also shown that low blood flow in the brain at rest is one of the earliest changes in dementia.

The aim of this study is to find out how cardiovascular conditions affect CVR and how this impacts of memory. CVR has not been well studied in humans. This is because the technology needed to make these studies possible has not been available. 

What does this project involve?

Dr Suri will use a new brain scanning technique to understand how and at what stage cardiovascular diseases affect CVR and memory.

Recent research has developed ‘dementia risk-assessment scores’. These predict a person’s chance of developing dementia based on their cardiovascular health history. However, to translate this scoring method to the real world this clinical research is needed.  

This project will involve 140 people from the UK Whitehall II Imaging cohort – a group of people who have already had annual heart health tests since they were 40 years old.

At 60 they also had brain scans and memory and thinking assessments. With this unique group of people Dr Suri will investigate how brain health in older age is linked to heart health in middle age. 

How will this project help people with dementia?

This study could produce a reliable new method of selecting people for clinical trials to prevent dementia. People with a low CVR could be included into trials for exercise intervention to reduce dementia risk.

CVR could also be used as a valuable marker to monitor progress in trials that are aimed at improving blood flow to the brain. Dementia risk scores could be used to identify people at high risk of dementia for treatments to delay or prevent the condition.