New research links high blood pressure in middle age to dementia in later life

High blood pressure – especially in middle age – is linked to dementia, the American Heart Association (AHA) has said in a statement.

A review of existing studies led AHA experts to conclude that high blood pressure “disrupts the structure and function of cerebral blood vessels”. This leads to damage of the white matter parts of the brain that are critical for cognitive function, and may promote dementia, including Alzheimer’s, they said.

The experts also pointed to “strong evidence” of a negative effect of mid-life high blood pressure on the brain’s function in later years.

The team called for further research to establish whether treating high blood pressure, especially in middle age, cuts the risk of suffering damage to parts of the brain later in life.

The statement, which was published in the AHA journal Hypertension, came after UK research earlier this year on more than four million people confirmed a link between high blood pressure and the risk of vascular dementia.

Vascular dementia is the second most common cause of dementia after Alzheimer’s disease and is caused by a reduction in blood flow to the brain resulting from a stroke or damage to small blood vessels.

It is thought to affect around 150,000 people in the UK and causes memory loss, communication problems and personality changes.

Overall, 850,000 people in the UK are living with dementia. According to the Alzheimer’s Society, this number will rise to more than two million by 2051 unless action is taken.

Chairman of the AHA’s writing committee Dr Costantino Iadecola said one of the problems with recommending blood pressure treatment that may help prevent dementia was that there are often years between the time a patient has high blood pressure and when the cognitive problems arise.

Long-term studies looking at when treatment should start to protect the brain are needed, he said.

He added: “We know treating high blood pressure reduces the risk of heart diseases such as heart attacks, congestive heart failure and stroke, and it is important to continue treating it to reduce the risks of these diseases.

“However, we need randomised controlled studies – which do prove cause and effect – to determine if treating high blood pressure, especially in middle age, will also decrease the risk of cognitive impairment later in life.”

Dr Doug Brown, director of research and development at Alzheimer’s Society, said: “There is growing evidence that high blood pressure is not only bad for your heart but also bad for your head.

“However, studies looking at this have so far been small and not over long enough periods of time to understand the cause and effect.

“Picking apart this link could help a lot of people to reduce their risk of dementia, which is why Alzheimer’s Society is funding several studies in this area.

“While there’s no silver bullet for dementia, it’s best to keep your blood pressure in check as part of a healthy lifestyle in order to lower your chances of developing the condition.

“We can’t say yet whether blood pressure treatments are able to reduce dementia risk as they do for risk of heart diseases – anyone who has questions about their medication should speak to their GP.”

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