Lowering blood pressure could prevent Alzheimer’s disease, according to new research.
A study of more than 9,000 over 50s found those who got it below the level normally recommended slashed their risk of memory problems by about a fifth.
They were also a sixth – 15 per cent – less likely to develop full blown dementia – a figure that may be conservative owing to the short duration of the trial.
It’s the first time a single intervention has been found to combat the devastating neurological condition that is expected to affect two million Britons by 2050.
Dr Maria Carrillo, chief science officer at the Alzheimer’s Association in the US, said: “Proof that lowering blood pressure can lower risk for dementia may be key to improving the lives of millions of people around the world.”
Participants who reduced their blood pressure to a top reading of 120 – instead of 140 – were 19 per cent less likely to develop mild cognitive impairment (MCI), a condition that often leads to dementia.
They also had fewer signs of damage on brain scans – and there were fewer cases of dementia.
Last year US authorities changed the definition of hypertension from 140mmGH to 120mmGH – allowing millions more people to access drugs to combat the problem.
The National Institute for Health and Care Excellence (NICE), the UK’s health body, is will announce whether it will follow suit later this year.
It would make 14 million more patients eligible for medication.
High blood pressure affects over half of people aged over 50 and more than three quarters of over 65s.
Principal investigator Professor Jeff Williamson, a gerontologist at Wake Forest School of Medicine in Winston-Salem, North Carolina, believes lowering blood pressure more than usually advised may hold the key to combating soaring rates of dementia.
He said: “As doctors treating older patients, we are encouraged to finally have a proven intervention to lower someone’s risk for MCI.”
This is defined as a decline in memory and thinking skills that is greater than expected with normal ageing. It’s a known risk factor for dementia.
Prof Williamson said: “In the study, we found just three years of lowering blood pressure not only dramatically helped the heart but also helped the brain.”
The SPRINT MIND study published in JAMA said hypertension has been identified as a potentially modifiable risk factor for MCI and dementia in previous observational research.
It included 9,361 volunteers recruited from across the US and Puerto Rico who had been diagnosed with hypertension but not diabetes or stroke.
They were chosen at random to achieve a systolic blood pressure goal of either less than 120 mmHG through intensive treatment – including drugs and lifestyle changes – or less than 140 mmHG which was the standard therapy.
They were then classified after five years as having no cognitive impairment, MCI or probable dementia.
The study was stopped early due to the success of the trial in reducing cardiovascular disease.
As a result, participants were on intensive blood pressure lowering treatment for a shorter period than originally planned.
This may have made it difficult to accurately determine the role of intensive blood pressure control on dementia cases.
Prof Williamson explained: “Although the study showed a 15 per cent reduction in dementia in the intensively controlled group, we were disappointed that the results did not achieve statistical significance for this outcome.
“Last week the Alzheimer’s Association agreed to fund additional follow-up of SPRINT MIND participants in the hope that sufficient dementia cases will accrue, allowing for a more definitive statement on these outcomes.”
The Alzheimer’s Association has now awarded more than $800,000 to support a follow up study which will involved the same people over another two years.
This will further investigate the impact of intensive blood pressure treatment on reducing risk of dementia.
Dr Carillo said: “SPRINT MIND 2.0 and the work leading up to it offers genuine, concrete hope.
“MCI is a known risk factor for dementia, and everyone who experiences dementia passes through MCI.
“When you prevent new cases of MCI, you are preventing new cases of dementia.
“The Alzheimer’s Association finds these data to be compelling, and is committed to getting clarity and certainty on the dementia outcome by following participants for a longer period of time.”
She added: “The Alzheimer’s Association is committed to getting the answers about treating and preventing Alzheimer’s and other dementias.
“We are filling the gaps in Alzheimer’s research, and – with the support of our donors and partners – we act rapidly to maximise opportunities.”
This was welcomed by Prof Williamson, who said: “Dementia takes longer to develop than MCI.
“Consequently, the early termination of the study likely affected the number of dementia cases detected.
“Further cognitive assessment of the SPRINT MIND study participants might discover enough additional cases of probable dementia to support a more definitive conclusion.”
High blood pressure is a leading risk factor for heart disease, stroke and kidney failure. A growing body of research suggests it may increase risk for dementia.
Dr Richard Hodes, director of the National Institute on Aging (NIA) in the US which funded the study, said: “Dementia continues to be a large public health challenge, and based on the primary results of this study, we still have yet to find an intervention strategy proven to reduce the risk of dementia.
“Nevertheless, the secondary results showing that intensive lowering of blood pressure may reduce risk for MCI, a known risk factor for dementia, gives us additional avenues to explore on the path to prevention.”
The researchers said an important conclusion is the intensive lowering of systolic blood pressure – when your heart beats and pushes the blood round your body – reduces the risk of heart attacks and stroke, and is safe for the brain.
by Mark Waghorn