There is more hope than ‘ever before’ that nearly half of dementia cases can be prevented or delayed, experts say.
Researchers have identified two new risks: high cholesterol and vision loss. These risks can be addressed to reduce the chance of developing this condition.
By addressing these factors – and 12 others – in childhood and throughout life, people will have the best chance of preventing or delaying dementia, even if they have a high genetic risk, researchers say.
According to the Third Lancet Commission on Dementia Prevention and Intervention, high cholesterol and vision loss are associated with 9% of all dementia cases.
It is estimated that 7% of cases are attributable to high, bad cholesterol levels starting at about age 40, and 2% of cases are attributable to untreated vision loss later in life.
Lead author Professor Gill Livingston from University College London (UCL) said the report “shows hope that we can prevent people from developing dementia, and more people than ever before”.
She told the PA news agency: “When I first became a doctor, and for a while afterwards, we thought dementia was just one of those things that happened to you relatively randomly, and that you couldn’t do anything about it. And if you got it, you got it.
“But now we know that’s not true. Even if you have genes that make you susceptible, these lifestyle changes will help you live longer in good health and it will take longer for you to get it.
“And for people in general, there are many things you can do individually to reduce your risk of dementia and increase the number of years you live a healthy life.
“I think that’s a remarkable bonus that we didn’t know about.”
According to Professor Livingston, one of the easiest things people can do to reduce their risk of dementia if they spend a large part of their day inactive is to get some exercise, either by walking or doing some seated exercise.
She added: “Give yourself a chance.
“What you do will not only reduce your risk of dementia, it will also increase the quality of your life now and may increase the quantity of your life and the quantity of your healthy life.
“Because I think people are afraid of a long and unhealthy life, but it should increase the amount of your healthy life.”
To reduce the risk of dementia throughout life, the Commission makes 13 recommendations to governments and citizens.
Examples include making hearing aids available to everyone with hearing loss, reducing exposure to harmful noise, and detecting and treating high cholesterol from about the age of 40.
Other recommendations include making screening and treatment for visual impairment accessible to all and providing children with a good education and ensuring they remain cognitively active in middle age.
Prof Livingston said: “We now have stronger evidence that longer exposure to risks has a greater effect and that risks work more strongly in people who are vulnerable.”
“Governments should reduce risk disparities by making healthy lifestyles as attainable as possible for everyone,” she added.
The two new factors that increase the risk of dementia come on top of the twelve previously identified by the commission: lower education, hearing loss, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption, traumatic brain injury, air pollution and social isolation. These factors are associated with 40% of all dementia cases.
The report, presented at the Alzheimer’s Association International Conference, found that hearing loss and high cholesterol (each 7%) are the risk factors associated with the highest percentage of people worldwide developing dementia.
This is followed by lower educational levels in early childhood and social isolation later in life (each 5%).
In the report, funded by Alzheimer’s Research UK, the experts write: “The potential for prevention is great and theoretically almost half of dementias could be prevented by eliminating these 14 risk factors.
“These findings offer hope.”
According to the Alzheimer’s Society, there are an estimated 982,000 people with dementia in the UK, with this number expected to rise to 1.4 million by 2040.
In a separate study published with the committee in the journal The Lancet Healthy Longevity, researchers modelled the economic impact of implementing some of these recommendations, using England as an example.
They found that public health interventions addressing risk factors for dementia could deliver up to £4 billion in savings in England by reducing dementia rates and helping people live longer, healthier lives.
Fiona Carragher, head of policy and research at the Alzheimer’s Society, which part-funded the research, said: “If we can help people reduce their risk of dementia and bring about the societal change needed, it could potentially mean hundreds of thousands fewer people in the UK developing dementia.”
Dr Jeremy Isaacs, NHS National Clinical Director for Dementia, said: “This research is really important because it suggests there are additional risk factors for dementia, meaning there are more opportunities for all of us to take action in our lives to reduce our risk of developing dementia or delay its onset.
“The findings also offer real hope that we can reduce the number of people suffering from this devastating disease.
“Ensuring people with dementia receive a timely diagnosis is a priority and NHS staff have worked hard to ensure the number of people diagnosed with dementia has increased significantly over the past year and is now at a record high, but we know there is more work to be done.”
Separate research presented at the Alzheimer’s Association International Conference found that the Alzheimer’s drug lecanemab also has long-term benefits, showing no additional safety risks associated with taking the drug for three years.
Lecanemab slows the early stages of the disease and is currently being assessed for approval by the UK medicines regulator.
Pharmaceutical company Eisai and biotechnology company Biogen reported that new clinical data indicate that more than 50% of patients who started treatment in the earliest stages of Alzheimer’s disease continued to show improvement after three years of treatment.
The findings also show that Alzheimer’s disease continues to worsen even after treatment is stopped, meaning that patients still benefit from continuing to take lecanemab.