Researchers analysing the health records of over 4 million people in the UK have confirmed a previously-reported link between high blood pressure and the risk of vascular dementia– the second most common cause of dementia after Alzheimer’s disease. The study is published today (Wednesday) in the journal Stroke.
Vascular dementia is caused by a reduction in blood flow to the brain resulting from a stroke or changes to small blood vessels. The condition is thought to affect around 150,000 people in the UK and causes symptoms like memory loss, communication problems and personality changes.
The team, led by researchers at the University of Oxford, analysed the electronic health records of 4.28 million people between 30 and 90. These people did not have a diagnosis of vascular disease or dementia, but the researchers were able to study their blood pressure measurements. Of these people 11,114 went on to receive a diagnosis of vascular dementia in an average follow-up period of seven years. The results showed that people between the ages of 30 and 50 were at a 62% greater risk of developing vascular dementia per 20mmHg above usual systolic blood pressure. For people between 51 and70 there was a smaller, 26% increased risk, and there was no evidence of high blood pressure affecting the risk of vascular dementia in those between 71 and 90.
The findings were followed up in a study in Oxford that has been following a group of people who had a stroke or transient ischaemic attack (sometimes called a ‘mini-stroke’). The team examined data from 1,680 people in the group who did not have dementia. Over a five-year period, 314 developed dementia. The researchers found that the risk of dementia was associated with the volunteer’s blood pressure five or more years prior to their stroke. This link was highest in those participants who were under the age of 75.
Dr Rosa Sancho, Head of Research at Alzheimer’s Research UK, said:
“There is mounting evidence to suggest that what’s good for the heart is good for the brain and maintaining good vascular health is one of the key things people can do to reduce their risk of dementia. This study has capitalised on the rich data held in electronic medical records to strengthen the link between high blood pressure and dementia risk, and suggest that midlife could be a particularly important window for reducing the risk of future vascular dementia.
“While it’s important that treatments are given to help control high blood pressure, this study doesn’t suggest that people without high blood pressure should be taking these medications specifically to reduce the risk of vascular dementia. Anyone with concerns about their vascular health should seek out the advice of their GP.”
“As well as maintaining a healthy blood pressure, there are other steps people can take to reduce their risk of dementia. The best current evidence suggests that not smoking, only drinking in moderation, staying mentally and physically active, eating a balanced diet, and keeping cholesterol levels in check can all help to keep our brains healthy as we age.”