TORONTO — Experts are warning that the COVID-19 pandemic could usher in a wave of increased dementia and Alzheimer’s worldwide through the ‘Trojan horse’ of neurological symptoms associated with long COVID, also known as long-haul COVID-19.
Alzheimer’s Disease International (ADI), which represents more than 100 Alzheimer’s and dementia associations, is calling on the World Health Organization and governments across the globe to invest funding into more research on the link between long COVID cases and dementia.
In a press release, ADI explained that even before COVID-19, it was predicted that dementia cases would rise from 55 million to 78 million by 2030, and associated health-care costs could rise to $3.5 trillion annually.
Now, experts believe millions more than that could face an accelerated risk of dementia due to COVID-19’s impact on the brain.
“Many dementia experts around the globe are seriously concerned by the link between dementia and the neurological symptoms of COVID-19,” Paola Barbarino, CEO of ADI, said in the release.
“We urge the WHO, governments and research institutions across the globe to prioritise and commit more funding to research and establish resources in this space, to avoid being further overwhelmed by the oncoming pandemic of dementia.”
Dementia is a general term describing symptoms that affect memory and executive functioning. A person with dementia may struggle to remember things, process thoughts and make decisions in a way that interferes with day-to-day activity. Alzheimer’s disease is the most common type of dementia. According to Alzheimer’s Association, more than 747,000 Canadians live with dementia.
Since the COVID-19 pandemic began, many of those who survive the virus have reported lasting cognitive impairment. A June survey looking at 1,000 Canadians who previously tested positive for COVID-19 found that more than 80 per cent of respondents had cognitive symptoms last for at least three months, while almost half said that their symptoms had lasted 11 months or longer.
Other studies have found that those hospitalized with COVID-19 experienced neurological symptoms, with one study across 13 countries finding that 82 per cent reported neurological issues.
And new research revealed at the recent Alzheimer’s Association International Conference found specific biomarkers associated with dementia and Alzheimer’s in patients hospitalized with COVID-19.
In the study, which looked at plasma samples from 310 COVID-19 patients admitted to New York University Langone Health, researchers observed that biomarkers of neuronal injury, neuroinflammation and Alzheimer’s disease were found at higher levels in COVID-19 patients who had reported neurological symptoms.
Dr. Alireza Atri, a leading expert in dementia, and part of a working group of scientists looking to study this issue, said in the release that we need to be wary of how COVID-19 could provide openings for dementia to flourish.
“We’re particularly concerned about the neurological symptoms of ‘long COVID-19’ such as loss of taste and smell, as well as cognitive problems like ‘brain fog,’ and difficulties with concentration, memory, thinking and language,” Atri said. “COVID-19 can cause damage and clotting in the brain’s micro vessels, immune dysfunction and hyperactivation, inflammation, and, last but not least, direct viral brain invasion through the olfactory pathways.”
He explained that when the “blood-brain barrier” is impacted, it is similar to a fortress wall being breached.
“Simply put, if you have a fortress and an enemy puts holes in your walls, you’re less likely to be able to withstand current and future attacks,” he said. “COVID-19 opens the gates in the same way that the Greek soldiers hiding in the wooden horse did. It gives easier access to things that can harm your brain.”
He added that we still have “a way to go in understanding this” but that anything that damages the brain’s defences makes it more vulnerable to neurological disorders showing up earlier.
In the short term, experts expect to see a temporary dip in dementia levels worldwide, simply because a large majority of those suffering from dementia are older, and COVID-19 has killed so many of the elderly. But they expect that we will see dementia impacting more and more people moving forward.
More research into the issue is important in order to make a plan for how to address a coming increase in dementia patients, Barbarino said.
“People at risk of developing dementia need to know about the potential impact of long COVID on their brain health,” says Barbarino. “We need people to be aware of the possible link between long COVID and dementia, so they know to self-monitor for symptoms and catch it in its tracks. Measures must be put in place to protect them.”