Millions of cases of dementia could be prevented or delayed by reducing risk factors such as smoking or air pollution, according to a major new study, although outside experts caution that such measures may only work to a certain extent.
This debilitating condition, which slowly robs people of their memory, cognitive abilities, language and independence, currently affects more than 55 million people worldwide.
Dementia is caused by a variety of diseases, the most common of which is Alzheimer’s.
A comprehensive review of the available evidence published in The Lancet journal on Wednesday said the “potential for prevention is very high” in the fight against dementia.
The study follows a previous report from 2020 that also emphasized the importance of prevention.
At the time, the international team of researchers estimated that 40 percent of dementia cases were linked to 12 risk factors.
These factors included low education level, hearing problems, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive drinking, brain injury, air pollution and social isolation.
The latest update added two more risk factors: vision loss and high cholesterol.
“Theoretically, about half of all dementia cases could be prevented by eliminating these 14 risk factors,” the study says.
The European Union rejected the new drug
Despite decades of research and billions of dollars spent, no cure or truly effective medication for dementia has been developed.
But since the beginning of last year, two Alzheimer’s treatments have been approved in the United States: Biogen’s lecanemab and Eli Lilly’s donanemab.
They work by targeting the build-up of two proteins — tau and amyloid beta — that are thought to be one of the main pathways through which the disease progresses.
However, the benefits of these drugs are modest, they have serious side effects, and they are often very expensive.
Unlike the US, the European Union’s drug regulator last week refused to approve lecanemab, and is still considering donanemab.
Some researchers are hopeful that the new drugs will prove effective, meaning they will pave the way for more effective treatments in the future.
Others prefer to focus on ways to prevent dementia in the first place.
Masood Hussain, a neurologist at the University of Oxford in Britain, said focusing on risk factors would be “far more cost-effective than developing high-tech treatments, which have so far been disappointing in their effects on people with established dementia”.
‘How much more could we have done?’
The Lancet study was welcomed by experts in the field, among whom there is little debate about the importance of prevention.
However, some say the idea should be put into perspective, given that about half of dementia cases are preventable.
It hasn’t been proven that risk factors directly cause dementia, as the study authors acknowledged.
For example, is it the dementia that is causing the depression, not the other way around?
It’s also hard to separate risk factors from one another, though researchers tried.
Some of these may be intrinsically linked, such as depression and loneliness, or smoking and high blood pressure.
Above all, many of the risk factors are social crises that have proven nearly impossible to fully address.
The study makes a variety of recommendations, ranging from individual recommendations – such as wearing a helmet when cycling – to government recommendations, such as improving access to education.
“It’s not clear whether we will be able to completely eliminate any of these risk factors,” neurologist Charles Marshall at Queen Mary University of London, told AFP.
“We already have public health programs to reduce smoking and hypertension (high blood pressure), so how much more can we do?”
Tara Speirs-Jones, a neuroscientist at the University of Edinburgh, said it was important “that we don’t blame people with dementia for their brain disease”.
He said this is because “it is clear that a large proportion of dementia is not preventable because of genes and things beyond people’s control, such as educational opportunities as children.”
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
