woman with dementia sitting in chair
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Older adults previously infected with COVID-19, especially women aged 85 or more years, show a substantially higher risk of developing Alzheimer’s disease within a year, according to the results of a new study from Case Western Reserve University in Cleveland.

The results indicate “a very scary prospect” for senior living providers and indicate the importance of coronavirus prevention measures for residents and staff members, a study co-author told McKnight’s Senior Living.  

The research, published in the Journal of Alzheimer’s Disease, found that older adults who contracted COVID-19 were 50% to 80% more prone to developing Alzheimer’s. The risk nearly doubled — from 0.35% to 0.68% — over a one-year period following a COVID infection. 

The findings were based on a retrospective observational study, so investigators can’t say whether COVID-19 triggered the new development of Alzheimer’s disease or whether it accelerates the disease’s emergence. But it’s certainly associated, said Pamela Davis, MD, PhD, a study co-author and a professor in the Center for Community Health Integration at the CWRU School of Medicine. 

“For people who have a concentration of older people living in a facility, the concept that for whatever reason following COVID there is an increase in diagnoses of Alzheimer’s disease is a very scary prospect,” Davis, also the Arline H. and Curtis F. Garvin Research Professor at the medical school, told McKnight’s Senior Living. “The need for care just goes up tremendously as cognitive abilities decline.”

The research

Investigators analyzed the electronic health records of 6.2 million older adults aged 65 or more years with no prior Alzheimer’s disease diagnosis who received medical treatment between February 2020 and May 2021. More than 400,000 people were in the COVID-19 study group, whereas 5.8 million were in the noninfected group.

Davis said there was a strong association between COVID infection and Alzheimer’s disease, particularly in women 85 and older; 2% of people in that age group received an Alzheimer’s diagnosis in the year following their COVID-19 infection.

“That’s a lot of people,” Davis said. “I think it emphasizes the need for prevention, in terms of immunization [against COVID], for both the residents and for the people who care for them.”

With age as the biggest risk factor for Alzheimer’s, Davis said it’s no surprise that the oldest adults have higher rates. But she said that researchers are seeing “something more devastating” for women and the “oldest of the old” when it comes to COVID-19 and dementia.

Next up

The study does not address whether COVID-19 treatments, such as Paxlovid, mitigate the excess risk for disease, something Davis said needs to be investigated.

“It probably doesn’t hurt, and it might help,” she said. 

She also said that she wants to see whether this is “a blip or a trend,” and whether it was just an observation early in the pandemic. 

Regardless, Davis said that the results emphasize the need to be careful — she said she is a big proponent of masking and social distancing when someone has a COVID-19 diagnosis, particularly in congregate care settings. And she cited vaccines as the best mechanism to limit the spread of disease.

“I don’t think we’ve explored thoroughly, as a field, the downstream consequences of getting COVID,” Davis said. “I think we need to prevent it to the greatest extent possible.”