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Dementia risk falls for millions as chance of developing the disease is now 13% lower than 2010

Dementia rates among men are falling three times quicker than they are in women, according to a major study.

Harvard University researchers found the risk of developing the incurable disorder has dropped by 13 per cent every decade since 1988. Rates have plummeted for men by 24 per cent every ten years, while for women it has been a more gradual decline (8 per cent). 

Men were previously far more at risk than females of suffering from dementia — but the risk between sexes has now levelled out, experts said. 

In 1995, the average European or American person over the age of 75 had a one in four chance of getting dementia. Today, it is now less than one in five. 

The researchers say healthier lifestyles and fewer smokers could be behind the drop in risk, because poor blood circulation — which is hugely influenced by diet, exercise and drinking — has a significant impact on the brain. 

But, despite the risk of developing the memory-robbing disorder being lower, there are still a growing number of people being diagnosed with dementia. This is because more and more people are being born in the developed world and people are living longer than they ever have.  

In the UK there are an estimated 850,000 people living with dementia, while in the US there are around 5million. These numbers are still projected to treble by 2050. 

But, if the current decline in rates continue, Harvard researchers say there could be far fewer cases in high-income countries than projected.

For the latest research, published in the journal Neurology, Harvard researchers reviewed data from seven large studies from around the world with a total of 49,202 people.

The studies followed men and women over-65 in Europe and North America for at least 15 years from between 1988 and 2015. 

Participants’ health was monitored with in-person exams, questionnaires and brain scans.

Of the near-50,000 volunteers, 4,253 (8.6 per cent) developed dementia, a general term for a decline in mental ability severe enough to interfere with daily life. 

Academics did not provide any raw numbers to illustrate exactly how the incidence rate changed over time.

They only gave data for how many people were diagnosed with dementia overall in each of the different cohorts.

But an analysis revealed rates dropped over time in each of the seven studies — at around 13 per cent per decade.

The papers found dementia incidence declined by 13 per cent per calendar decade and that the drop was ‘consistent across studies’.

The fall, which experts said was ‘consistent across studies’, was more pronounced in men (24 per cent) than in women (8 per cent).   

The data also included a separate assessment of Alzheimer’s disease, a specific form of dementia that accounts for seven in 10 dementia cases.

Rates for Alzheimer’s also had a similar drop in incidence, falling by about 16 per cent per decade.   

But the study found that age was still a huge risk factor for developing dementia. The risk was 16 times greater for those above the age of 85, compared to those under 70. 

Dr Albert Hofman, chairman of the department of epidemiology at the Harvard School of Public Health and lead author of the research believes improved heart health and education are behind the falling rates.

There is now a growing understanding that poor blood circulation – which is hugely influenced by diet, exercise and drinking – has a significant impact on blood vessels in the brain.

Education is also now known to have a protective effect, with those who receive a better schooling more likely to continue to carry out complex thinking throughout their lives – which reduces dementia risk by keeping the brain active.   

Dr John Morris, director of the Center for Aging at Washington University in St. Louis, told The New York Times: ‘It is such a strong study and such a powerful message. It suggests that the risk is modifiable.’ 

Gill Livingston, from University College London in the UK, said the findings ‘show again that some of dementia is already being prevented with the changes which have taken place in these societies’.

She added: ‘We know that worldwide 40 per cent of dementias are potentially preventable.

Sara Imarisio, research head at Alzheimer’s Research UK, told The Times newspaper there: ‘We know recent decades have seen a radical decline in smoking rates for men.  While many people may have been persuaded to stop smoking due to an increased risk of cancer or heart disease, it is also a key risk factor for dementia.’

Last week a major study said hundreds of thousands of people could ward off dementia by adopting a healthy lifestyle. 

Some 40 per cent of cases could be avoided or delayed, a comprehensive review of the evidence concludes.

Eating less, exercising more, and cutting out alcohol and cigarettes significantly reduce the risk of developing dementia in later life, researchers said.  

A team of 28 world-leading dementia experts, who conducted the review for the Lancet medical journal, identified 12 different controllable factors which contribute to dementia risk.   

Hundreds of thousands of people could ward off dementia by adopting a healthy lifestyle, a major study has found.

Some 40 per cent of cases could be avoided or delayed, a comprehensive review of the evidence concludes.

Eating less, exercising more, and cutting out alcohol and cigarettes significantly reduce the risk of developing dementia in later life, researchers said. 

These lifestyle habits – together with environmental factors, medical history and education – are responsible for roughly 340,000 out of Britain’s 850,000 dementia cases, the study suggests.

A team of 28 world-leading dementia experts, who conducted the review for the Lancet medical journal, identified 12 different controllable factors which contribute to dementia risk. 

For decades experts believed dementia was a matter of fate – a cruel quirk of genetics and ageing.

But in recent years scientists have become increasingly aware that dementia is not inevitable, and in fact the way people live their lives increases the risk of developing the condition in old age.

There is now a growing understanding that poor blood circulation – which is hugely influenced by diet, exercise and drinking – has a significant impact on the brain.

Education is also now known to have a protective effect, with those who receive a better schooling more likely to continue to carry out complex thinking throughout their lives – which reduces dementia risk by keeping the brain active.

Air pollution, as well as depression and social in old age, also increases the risk.

In 2017 a previous Lancet review identified nine elements which contributed to dementia risk.

The new paper updates this and adds three new risk factors – alcohol intake, air pollution and head injuries.

The researchers – who include world-leading British scientists from University College London, Cambridge, Exeter, Edinburgh and Manchester – stressed that the majority of dementia risk is down to genetics and other uncontrollable factors. 

But they said the new findings show people have a huge degree of power to determine their own fate.

Politicians, meanwhile, must take responsibility for reducing some of the risk, they said – particularly by addressing the growing problem of air pollution.

Researcher Professor Clive Ballard of the University of Exeter, said: ‘Our findings present an exciting opportunity to improve millions of lives across the world by preventing or delaying dementia, through healthier lifestyle to include more exercise, being a healthy weight and stopping smoking, and good medical treatment of risk factors like high blood pressure. 

‘One important less well known risk factor is hearing loss in mid-life, with emerging evidence that wearing hearing aids may be protective.

‘This presented an important public health message – if you’re having hearing problems, getting tested in mid life and wearing a hearing aid if needed could have multiple benefits.

‘This analysis shows there’s real potential to improve brain health by taking action.’

The researchers said one of the biggest controllable factors is poor education, which is responsible for 7 per cent of dementia cases.

Hearing loss in middle age is responsible for 8 per cent of cases and brain injury for 3 per cent.

High blood pressure from middle age contributes 2 per cent, obesity 1 per cent and drinking more than 21 units a week 1 per cent. 

Smoking in old age contributes 5 per cent of cases, physical inactivity 2 per cent, diabetes 1 per cent, depression 4 per cent, isolation 4 per cent and air pollution 2 per cent.

Study leader Professor Gill Livingston of UCL, who presented the paper yesterday to the Alzheimer’s Association International Conference, said politicians could do much to reduce these risks. 

‘Our report shows that it is within the power of policy-makers and individuals to prevent and delay a significant proportion of dementia, with opportunities to make an impact at each stage of a person’s life.

‘We can reduce risks by creating active and healthy environments for communities, where physical activity is the norm, better diet is accessible for all, and exposure to excessive alcohol is minimised.’

Fiona Carragher, director of research at the Alzheimer’s Society, which part-funded the study, said: ‘While we don’t have all the answers yet, we can take action now to tackle the risk factors within our control, including excessive drinking, obesity and high blood pressure.     

‘Meanwhile, we need public health policies to address other factors, such as air pollution and inequalities in childhood education.’

Dr Rosa Sancho, head of research at Alzheimer’s Research UK, added: ‘While there’s no sure-fire way of preventing dementia, the best way to keep your brain healthy as you age is to stay physically and mentally active, eat a healthy balanced diet, not smoke, drink only within the recommended limits and keep weight, cholesterol and blood pressure in check.

‘With no treatments yet able to slow or stop the onset of dementia, taking action to reduce these risks is an important part of our strategy for tackling the condition.

‘This report underlines the importance of acting at a personal and policy level to reduce dementia risk.’

Professor Jennifer Rusted of the University of Sussex, added: ‘The big picture here is that an individual’s dementia risk is a complex of many factors that impact differently through the lifespan, and lifestyle choices and changes can quite significantly reduce risk of dementia in later life’If you can work to mitigate any of these multiple factors then you can at least push back the age at which cognitive impairment emerges to affect your independent living and quality of life.’

 

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