Risk for Developing Alzheimer’s Disease Increases by 50-80% In Older Adults Who Caught COVID-19

Summary: The risk of developing Alzheimer’s disease almost doubled in older people during the one-year period following COVID-19 infection.

Source: Case Western Reserve

Older people who were infected with COVID-19 show a substantially higher risk—as much as 50% to 80% higher than a control group—of developing Alzheimer’s disease within a year, according to a study of more than 6 million patients 65 and older.

In a study published today in the Journal of Alzheimer’s Disease, researchers report that people 65 and older who contracted COVID-19 were more prone to developing Alzheimer’s disease in the year following their COVID diagnosis. And the highest risk was observed in women at least 85 years old.

The findings showed that the risk for developing Alzheimer’s disease in older people nearly doubled (0.35% to 0.68%) over a one-year period following infection with COVID. The researchers say it is unclear whether COVID-19 triggers new development of Alzheimer’s disease or accelerates its emergence.

“The factors that play into the development of Alzheimer’s disease have been poorly understood, but two pieces considered important are prior infections, especially viral infections, and inflammation,” said Pamela Davis, Distinguished University Professor and The Arline H. and Curtis F. Garvin Research Professor at the Case Western Reserve School of Medicine, the study’s coauthor.

“Since infection with SARS-CoV2 has been associated with central nervous system abnormalities including inflammation, we wanted to test whether, even in the short term, COVID could lead to increased diagnoses,” she said.

The research team analyzed the anonymous electronic health records of 6.2 million adults 65 and older in the United States who received medical treatment between February 2020 and May 2021 and had no prior diagnosis of Alzheimer’s disease.

They then divided this population two groups: one composed of people who contracted COVID-19 during that period, and another with people who had no documented cases of COVID-19. More than 400,000 people were enrolled in the COVID study group, while 5.8 million were in the non-infected group.

This shows an older man in a face mask
The researchers say it is unclear whether COVID-19 triggers new development of Alzheimer’s disease or accelerates its emergence. Image is in the public domain

“If this increase in new diagnoses of Alzheimer’s disease is sustained, the wave of patients with a disease currently without a cure will be substantial, and could further strain our long-term care resources,” Davis said.

“Alzheimer’s disease is a serious and challenging disease, and we thought we had turned some of the tide on it by reducing general risk factors such as hypertension, heart disease, obesity and a sedentary lifestyle.

“Now, so many people in the U.S. 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.”

Rong Xu, the study’s corresponding author, professor of Biomedical Informatics at the School of Medicine and director of the Center for AI in Drug Discovery, said the team plans to continue studying the effects of COVID-19 on Alzheimer’s disease and other neurodegenerative disorders—especially which subpopulations may be more vulnerable—and the potential to repurpose FDA-approved drugs to treat COVID’s long-term effects.

Previous COVID-related studies led by CWRU have found that people with dementia are twice as likely to contract COVID; those with substance abuse disorder orders are more likely to contract COVID; and that 5% of people who took Paxlovid for treatment of COVID symptoms experienced rebound infections within a month.

About this aging, COVID-19, and Alzheimer’s disease research news

Author: Megan Hahn
Source: Case Western Reserve
Contact: Megan Hahn – Case Western Reserve
Image: The image is in the public domain

Original Research: Open access.
Association of COVID-19 with New-Onset Alzheimer’s Disease” by Pamela Davis et al. Journal of Alzheimer’s Disease


Association of COVID-19 with New-Onset Alzheimer’s Disease

An infectious etiology of Alzheimer’s disease has been postulated for decades. It remains unknown whether SARS-CoV-2 viral infection is associated with increased risk for Alzheimer’s disease.

In this retrospective cohort study of 6,245,282 older adults (age ≥65 years) who had medical encounters between 2/2020–5/2021, we show that people with COVID-19 were at significantly increased risk for new diagnosis of Alzheimer’s disease within 360 days after the initial COVID-19 diagnosis (hazard ratio or HR:1.69, 95% CI: 1.53–1.72), especially in people age ≥85 years and in women.

Our findings call for research to understand the underlying mechanisms and for continuous surveillance of long-term impacts of COVID-19 on Alzheimer’s disease.

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  1. I’m 79 years old get Cov2 PCR positive Test at 08/04/22 no any symptoms but lost a lot of body weights and muscles feel good ,waiting now for Alzheimer ‘Disease at next 10 years Thanks for patients dear Alzheimer
    p.s. was fully vaccinated before case

  2. T had confirmed Covid 19 3 times,since October 30,2019. I was in hospital at Emory U,enrolled in a study,Even after 4 test,it was unconfirmed,until they accounted,my blood volume,had dropped,by halve. I got Lovenox,ate any thing,just a little,walked to prevent,and dispel clots. Went home,had to return,for 6 more days,went home,took ginger root,made mustard,honey plasters,to remove the edema,from my lungs,great Gram trick from the 1918 Flu,drank Pedialyte,took Tylenol Arthritis,and 7 brain supplements,vitamin D,and retrained my brain,short term memory,open all the window,took oregano oil,rosemary oil,and most of all,I kept the fever,at Bay,and with my Will,fought,gall stones,bleeding from every orifice. I am still my self,at 75 years,in July. I kept a journal. The body,brain,needs time,and I was alone. I have had Covid,2 more times,much milder,mostly fatigue,slight fever,lack of olfactory,effecting taste,soft fragrances.Regular daily follower.

  3. So these are people diagnosed with new onset Alzheimer’s Disease after getting COVID. It does not imply that COVID causes Alzheimer’s nor that the vaccine causes it- just that people who caught COVID have a higher incidence of being diagnosed with Alzheimer’s. If you read the actual published article the authors state “It remains unknown whether SARS-CoV-2 viral infection is associated with increased risk for Alzheimer’s disease”. Another possibility unexplored by the authors is that people who have unrecognized Alzheimer’s are more susceptible to COVID. All-in-all not the best study and a poor use of statistics.

  4. Or maybe those who are pre-Alzheimer’s are more likely to contract COVID? The article even says itself “Previous COVID-related studies led by CWRU have found that people with dementia are twice as likely to contract COVID.” Since the study comes pretty close to twice the risk of getting Alzheimer’s, is it possible that the patient was in early stages, not diagnosed, and the Alzheimer’s led to an increased risk of COVID rather than the other way round?

  5. Makes no sense. Ever heard of ANY other type of cold/flu leading to an increase in Alzheimer’s? This is the vaccine.

  6. But let’s deny and ignore the fact that over 95% of these people recently got a vaccine (that didn’t work) that’s causing all sorts of other medical issues (blood clots, heart inflammation, etc).

    But I guess this is simply darwinism at work.

    1. My mum had covid in Aug 2020 before the rollout of any vaccines. The cognitive symptoms were most pronounced for her and sadly she has never fully recovered. Ultimately, covid has significantly worsened her dementia. If you check with caregivers you will find that this is not uncommon in the elderly population. The brain, like so many tissues in our body, has ACE2 receptors which are the virus’ entrypoints into the body. And that is why covid is such a nasty multisystemic illness.

  7. I had covid and am only 36 yet I feel like my brain just doesn’t work anymore on some things. I believe this study could be true as the infections triggers different things in different people.

    1. Same here. I’m 47. I regularly speak publicly and I rarely use notes or script words. I’ve been doing this for 20 years in politics, education, and industry, but Covid wrecked my brain. I spoke to 300 people this morning and struggled at times because my brain couldn’t quite up. It’s maddening. Also, for Mike- I’m not vaccinated.

  8. Now can we know how many of these people received a covid vaccine? And why is it assumed that catching covid causes this issue and no one will look at the other possibility that it is the vaccine causing it?

    1. It must be difficult for you to live in a world where you are so much smarter than everyone else.

    2. It is ALL worth investigating.
      Both vaccine and Covid .
      And causation regarding Both.
      I tend to agree that its the illness, but I also agree.
      So you are correct also.

    3. They used control groups. Read the article and if you don’t understand what control groups are then look it up.

    4. The study gathered information on patients beginning February 2020 through May of 2021 (16 months). Vaccines for COVID-19 were not approved or available until January 2021, the last five of the sixteen months the study was gathering data. Even if the study was 15 months and assuming they collected the same number of participants (patients) each month, the first two thirds of the data reflects that getting a COVID infection prior to vaccine availability demonstrates a significant increase in new Alzheimers diagnoses.

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