New Alzheimer’s diagnoses are more common among older people who have had Covid-19, study finds

The study does not show that Covid-19 causes Alzheimer’s, but it adds to the growing body of research establishing links between coronavirus infection and cognitive function.

“In the Alzheimer’s disease brain, pathology begins to accumulate about 20 years before symptoms begin,” said Dr. David Holtzman, a neurologist who directs a research lab focused on the disease. Alzheimer’s at Washington University School of Medicine in St. . Louis People would need to be followed for decades after a Covid-19 infection to prove it as a cause, he said.

Instead, a Covid-19 infection could cause inflammation that can exacerbate changes already occurring in the brain, experts say.

“The brain has its own immune response to the pathology involved [Alzheimer’s] “The disease progresses,” said Holtzman, who was not part of the new study. “When there are other things that cause inflammation in the body that can affect the brain, what probably happens is that it can even amplify the process that’s already going on.”

Other viruses can cause similar inflammation, experts say.

Covid “is another one of many dozens of potential risk factors that I talk to my patients about,” said Dr. Richard Isaacson, a neurologist and director of Florida Atlantic University’s Brain Health Center. He also did not participate in the new study, but is a researcher focused on preventing the risk of Alzheimer’s disease.

“I tell people to get their shingles shot. I tell people to get their annual flu shots and Pneumovax,” and to exercise and eat a brain-healthy diet.

Still, “when there’s smoke, there’s fire at some point,” he said. “I really think this is something that at least needs to be paid attention to.”

The latest study, published last week in the Journal of Alzheimer’s Disease, found that there were about seven new diagnoses of Alzheimer’s disease for every 1,000 older people who had a documented case of Covid-19 last year, compared to about five new diagnoses for Alzheimer’s disease. every 1,000 that did not.

Heather Snyder, vice president of medical and scientific relations for the Alzheimer’s Association, notes that the broader implications of the pandemic could have influenced the study’s results.

“The pandemic introduced severe delays for people seeking medical diagnoses such as Alzheimer’s, meaning these results could be driven by those who already had Alzheimer’s when they were infected but had not yet sought a formal diagnosis,” he said. to say.

The study authors, along with Snyder and other experts, also identify this work as a call for more research into the underlying mechanisms of Alzheimer’s disease that could explain the association.

In the new study, the Alzheimer’s diagnosis was “mostly tentative,” said Dr. Eliezer Masliah, director of the Division of Neuroscience at the National Institute on Aging at the National Institutes of Health.

Masliah, who was not involved in the study, said there is evidence that Covid-19 could “trigger cognitive decline”, but there are new ways to specifically confirm the link to Alzheimer’s.

A next step would be to follow people at risk of Alzheimer’s after a Covid-19 infection long-term to track biomarkers found in blood and brain scans.

“In the next two years, we will have a lot of very important information,” Masliah said. And it’s an “extremely important issue” to watch, given the scale of the disease.

“Imagine how many millions of people over 60 or 65, like me, have had Covid. Let’s say 5% or 10% or even 1% are at risk,” he said.

“Wow. We’re looking at a lot of people in the next few years who could be added to the already very large epidemic of Alzheimer’s disease that we have.”

About 6.5 million people over the age of 65 are living with Alzheimer’s, according to estimates from the Alzheimer’s Association. And it was the seventh leading cause of death in the US in 2020, according to data from the US Centers for Disease Control and Prevention.

“Alzheimer’s disease is a serious and challenging disease, and we thought we had changed the course a bit by reducing general risk factors such as hypertension, heart disease, obesity and a sedentary lifestyle,” he said. said Dr. Pamela Davis, Research Professor. at Case Western Reserve University and co-author of the new study.

“Now, so many people in the United States have had Covid, and the long-term consequences of Covid are still emerging. It is important to continue to monitor the impact of this disease on future disability.”

Leave a Reply