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More than 55 million people worldwide suffer from dementia, a number expected to almost triple by 2050. But addressing 14 risk factors throughout life – starting in childhood – could prevent or delay nearly half of cases, according to a major report by 27 dementia experts.
Based on a review of the latest evidence, Wednesday’s report by the Lancet Commission on the prevention, intervention and treatment of dementia adds two risk factors – high cholesterol and vision loss – to the 12 others previously identified in the 2020 report. The existing risk factors are lack of education, head injury, physical inactivity, smoking, excessive alcohol consumption, hypertension, obesity, diabetes, hearing loss, depression, air pollution and infrequent social contact.
The research team wanted to collect and “add evidence to give individuals and governments accessible, reliable information and to set a research agenda by highlighting what we do not know,” said the main author of the report Dr. Gill Livingston via email. “Progress in preventing and treating dementia is accelerating.”
12 initial risk factors are associated with 40% of cases, but a new report shows that addressing 14 risk factors can help eliminate or delay 45% of dementia cases, said Livingston, professor of geriatric psychiatry at University College London.
High cholesterol in middle age around age 40 is associated with 7% of dementia cases, and untreated vision loss in late life is associated with 2% of cases.
Risk factors associated with the largest proportion of people developing dementia worldwide are high cholesterol, hearing loss, lack of education in early life and social isolation in later life, the authors found.
This “critical” update calls attention to two risk factors that preventive neurologist Dr. Richard Issacson says clinical practice has been evaluating it for more than a decade. “Right now the evidence is getting what is recommended for patients,” said Isaacson, director of research at the Institute of Neurodegenerative Diseases in Florida, who was not involved in the new study.
Affects brain function
The report did not determine whether these risk factors directly lead to dementia, experts said. It is possible that some risk factors may be early signs of an impending diagnosis of dementia, meaning that removing these factors may not reduce the risk of the disease, said Dr Klaus Ebmeier, Chair of the Foundation for Old Age Psychiatry at the University of Oxford. , in a news release. Ebmeier was not involved in the study.
But other research has provided theories about the relationship between these vulnerabilities and the risk of dementia.
The link between excess body fat and dementia, for one, may be due to the involvement of body fat in the metabolic and vascular processes associated with the accumulation of beta-amyloid protein, a hallmark of Alzheimer’s disease.
Exercise may help prevent dementia by increasing levels of a protein known to strengthen communication between brain cells, according to a January 2022 study. Exercise may also reduce inflammation, which kills nerve cells. And being socially engaged can help people reduce stress and access better health care.
Education is also important for several reasons. “Most importantly it makes the brain more resistant to damage, so people can have changes but still work well,” Livingston said. “It also helps people make good choices by allowing them to think about the evidence in a more educated way, and it’s linked to getting a better job, and money gives more choices, for example, in health care and where to live.”
The full mechanism of this risk factor should be investigated further, said American Academy of Neurology fellow Dr. Glen R. Finney, who was not involved in the study.
The explanation for these findings could be “a combination of promoting physical development and brain health, preventing damage to the brain, and increasing and maintaining brain stimulation, which also helps brain health and function,” he added. Finney, director of the Geisinger Memory and Cognition Program in Wilkes Barre, Pennsylvania.
This may explain the increased risk that can be caused by vision or hearing loss and air pollution.
How well a person can hear or see affects their ability to engage with their environment, have meaningful interactions with others and be physically active, all of which are sensory inputs that stimulate the brain and build cognitive reserve, Isaacson said.
“If you don’t use it, you lose it,” he said, adding that giving him a hearing aid or glasses often gives him a new lease on life.
Researchers are still trying to understand what components of air pollution may be responsible for the link with dementia risk, but particles have been found in the buildup of amyloid plaques in the brains of people with Alzheimer’s, Isaacson said. Living near a highway is also linked to a higher risk of dementia.
A call to action
Many of these risk factors can be addressed by the individual themselves, said Dr. Susan Kohlhaas, executive director of research at Alzheimer’s Research UK, in a news release.
“But others, like air pollution and early childhood education, are bigger than individuals and communities,” said Kohlhaas, who was not involved in the study. “Addressing them will require structural changes for society to give everyone the best chance to live a healthy life, free from the effects of dementia. Public health leaders should not ignore this message.
Based on risk factors, the authors also recommend 13 policy and lifestyle changes to help prevent or better manage dementia.
Policy guidelines for government agencies include ensuring quality education is available to all and providing information on the risks of smoking and excessive alcohol consumption and ways to stop, as well as price control and the prevention of smoking in public places.
Individuals should participate in cognitively stimulating activities, use head protection in contact sports or when riding a bicycle, and exercise regularly.
Maintaining a healthy weight and treating obesity as early as possible also helps prevent the risk of diabetes. The authors also recommend that people maintain a systolic blood pressure of 130 mmHg – millimeters of mercury – or less starting at age 40.
Treatment for depression, hearing loss, vision loss and high cholesterol is also important.
If you can’t move to an area with less air pollution, what you can do is use a HEPA filter at home and avoid using a wood- or coal-burning oven or heating, experts say.
The worldwide health and social impact of dementia has been estimated at more than $1 trillion annually. But implementing some of these guidelines could save the UK, for example, around €4.2 billion, according to a modeling study published alongside the report.
“Even in the case of dementia, these measures do not prevent, the quality of life is better for people … who have overcome the risk,” Finney said by email. “And dementia-specific drugs like acetylcholinesterase inhibitors and memantine can help and should be used. We need to fight neurological nihilism – we can protect and help the brain and we should!
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