High blood pressure in mid-life linked to dementia
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 to the white matter parts of the brain that are critical for cognitive function, and may promote dementia, including Alzheimer's, they said.
They 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 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 cause 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 later 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."