Startling new evidence that looking after your heart helps avoid Alzheimer’s

THEY are among our most devastating killers: heart disease and dementia. And now, astonishing new evidence from the world’s leading experts suggests these two diseases, which blight the lives of millions of Britons, are inextricably linked.

Doctors suspect well-known cardiovascular risk factors – including poor diet, obesity and conditions like high blood pressure and diabetes – not only damage the heart but also quietly wreak havoc on the tiny, delicate blood vessels supplying the brain. The implications are profound and could completely overhaul the way both conditions are treated within a generation. In short, it means each one of us can reduce our risk of dementia simply by taking steps to improve our diet and lifestyle.

As British Heart Foundation spokesman Professor John Deanfield, of University College Hospital, London, explains: ‘We now know we can at least delay dementia in many cases, and may even prevent it by tackling heart disease head-on.’

The burden of caring for dementia patients is a staggering £26 billion a year, more than the cost of cancer (£9.4 billion) and heart disease (£9 billion) combined. But the emerging picture is one of hope: there are steps we can all take to protect ourselves. Here we look at the exciting science uncovering links between heart health and dementia that could one day lead to new tests to identify those most at risk well before symptoms begin, and new drugs to stave off the worst effects.

I T’S NEVER TOO EARLY TO START TAKING CARE

THE key, say researchers, is the state of the heart and circulatory system in mid- life – roughly between 40 and 65. Those with poorer heart health during this stage are more likely to develop cognitive decline 20 years later. But does someone in their 30s or early 40s really need to worry about ‘old-age’ illnesses such as heart disease and dementia?

Dr Laura Corr, consultant cardiologist at the Harley Street Clinic, says: ‘All the data shows that your health in mid-life predicts where you’re going to end up.’

Pressure on the arteries can cause them to stiffen, become blocked with fatty plaques and narrow, all of which restricts blood flow to the tiny, delicate blood vessels in the brain.

Now scientists believe at least a third of dementia cases may be linked with circulation and potentially preventable.

Dr James Pickett, Head of Research at the Alzheimer’s Society, says: ‘With no new dementia drugs in over 15 years, prevention is key, and evidence suggests that getting regular exercise, eating a healthy, balanced diet, not smoking and keeping blood pressure in check can all help lower risk of cognitive decline.’

Dementia affects 850,000 people in the UK – someone is diagnosed every three minutes – with that number expected to pass one million by 2025. The most common type, Alzheimer’s, is thought to account for between 60 and 80 per cent of cases. Professor Roxana Carare, a specialist in anatomy of the brain at the University of Southampton, says: ‘A growing number of researchers don’t use the term Alzheimer’s or dementia any more. We call it vascular cognitive i m p a i rmen t , because we recognise t hese problems all come from the blood vessels.’

KEEP BLOOD PRESSURE LOW

ONE of the most important studies ever published on dementia suggests reducing blood pressure significantly reduces risk of the brain disease. The SPRINT-MIND study, reported at the Alzheimer’s Association International Conference in Chicago last July, followed nearly 10,000 patients with high blood pressure, also known as hypertension, over three years.

It found those who reduced it to healthy levels had a lower risk of mild cognitive impairment – memory problems – and dementia.

High blood pressure places more force on artery walls, making them stiffer and less pliable. This makes it hard for oxygen- rich blood to flow freely through the small blood vessels in the brain. Scientists think this may deprive brain cells of the nutrients they need and increase the risk of mini- strokes, both of which may lead to dementia. Even more interesting are suggestions that the earlier doctors treat high blood pressure, the better the chances of avoiding dementia. Jonathan Schott, professor of neurology at the Dementia Research Centre at the UCL Institute of Neurology, says: ‘Early mid-life seems to be the most important time to get blood pressure under control – not only to reduce heart disease and stroke, but also dementia.’

Funded by the BHF, Alzheimer’s Research UK and the Medical Research Council, Prof Schott and his team are in the final stages of a major study tracking hundreds of British men and women born in the same week in 1946 who had blood press ure monitored f r om their 30s. The results, to be published later this year, will reveal how blood pressure in midlife impacts on brain health 40 years later.

SCAN SPOTS DEMENTIA BEFORE IT HAPPENS

FOR decades, scientists have searched for a test that can spot dementia in its earliest stages. A breakthrough has remained elusive but new research shows

In the 1960s more than 7 out of 10 heart attacks in the UK were fatal. Today 7 in 10 people survive.

promise. Last November, Professor Deanfield’s group at UCL developed a method to measure the intensity of blood flow travelling along the carotid artery, which supplies blood through the neck to the brain.

When carried out in midlife, the simple ultrasound scan identified those at risk of cognitive decline, particular in relation to language and memory. If the carotid artery is healthy, it is elastic and flexible and cushions the physical pulse which comes from the heart when it beats. This process protects the delicate blood vessels deeper in the brain.

But age and problems such as high blood pressure and diabetes, stiffens the arterial walls.

The heart’s pulse is no longer cushioned and the intensity of blood flow, known as pulsatility, increases and causes damage over time to brain cells.

The team studied scans carried out on more than 3,000 civil servants in mid- life, and followed them up for 15 years to measure their cognitive abilities. Those with the most intense blood flow – and therefore potentially the stiffest arteries - were 50 per cent more likely to be suffering from cognitive decline than those with the least intense pulse.

The test could be used to identify people at risk of heart disease and dementia who could benefit from preventative drugs.

‘Potentially, this could be a test to spot cognitive decline in middle-aged adults, well in advance of actual symptoms,’ says Dr Scott Chiesa, of UCL’s Institute of Cardiovascular Science.

COULD STATINS BE THE ANSWER?

STATINS are taken by millions of Britons to slash their risk of heart disease and heart attacks. But could similar medicines be used to protect the brain from the ravages of dementia? The answer is, possibly, yes. A key factor in the progression of heart disease is atherosclerosis, where arteries become inflamed and clogged with fatty substances called plaques, or atheroma.

These plaques cause arteries to harden and narrow, restricting blood flow and oxygen supply and increasing the risk of clots that could potentially block the flow of blood to the heart or brain.

Atherosclerosis has few symp- toms and many people are unaware they have it. Statins are thought to lower levels of harmful cholesterol in the blood, known to play a key role in the build-up of atheroma, and may also dampen down artery inflammation.

Research suggests such inflammation in the brain could be linked to cases of dementia, and a study funded by Alzheimer’s Research UK is i nvestigating whether blocking the chemical pathways that lead to inflammation can reduce t he risk of cognitive decline. The aim is to find potential treatments – which could prove similar to those already used to treat heart disease.

Dr Patrick Strangward, from Manchester’s Faculty of Biology, Medici n e a n d Healt h , said: ‘ Inflammatory processes that occur in heart blood vessels also occur in the brain, so treatments that protect against cardiovascular disease are likely to help prevent vascular dementia, too.’

NEW DRUGS ARE COMING

SINCE 2002, more than 100 promising drugs to treat Alzheimer’s have entered clinical trials. Every single one has failed. The main problem is the brain changes that cause it occur decades before symptoms emerge.

Now, thanks to better understanding of the vascular causes of dementia, new medication for those at risk but not necessarily with symptoms may be close.

Scientists at Southampton are investigating if dementia could be tackled by improving the brain’s vascular ‘waste disposal system’.

As cells – including brain cells – go about their job, consuming or producing energy, they produce waste by- products. These are eliminated via very thin channels – one millionth of the thickness of a human hair – within the walls of the blood vessels. The Southampton team is investigating whether damage to blood vessels stops the brain eliminating waste properly.

Dr Strangward is convinced diet and lifestyle are key to prevention – and patients should not rely solely on medication. ‘Once the structural changes have occurred, like shrinkage of the brain, it can’t be recovered.

‘ But we’re getting better at detecting subtle changes in cognition, so in time we’ll be able to deliver therapies much earlier.’