Risk Factor for Alzheimer Disease Increases by up to 80% in Older Adults Who Had COVID-19

Older individuals who were infected with COVID-19 show a substantially higher risk of developing Alzheimer disease (AD) within a year than those in the control group, according to the results of a study of more than 6 million individuals aged 65 years and older.

In the study, published in Journal of Alzheimer’s Disease, investigators also reported that the highest risk was observed in women aged 85 years and older.

“The factors that play into the development of [AD] have been poorly understood, but 2 pieces considered important are prior infections, especially viral infections, and inflammation,” Pamela Davis, Distinguished University Professor and the Arline H. and Curtis F. Garvin Research Professor at the Case Western Reserve School of Medicine, said in a statement. “Since infection with [severe acute respiratory syndrome coronavirus 2] has been associated with central nervous system abnormalities including inflammation, we wanted to test whether, even in the short term, [COVID-19] could lead to increased diagnoses.”.

The results showed that the risk of developing AD in older individuals nearly doubled to 0.68% from 0.35% over a 1-year period, following a COVID-19 infection.

Investigators analyzed anonymous electronic health records of approximately 6.2 million individuals aged 65 years and older in the United States who received medical treatment between February 2020 and May 2021. The individuals also had no prior diagnosis of AD.

The population was divided into 2 groups: individuals who contracted COVID-19 during the time period and those who did not. Investigators reported that more than 400,000 individuals had COVID-19 and 5.8 million did not.

“If this increase in new diagnoses of [AD] 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. “[AD] 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.”

The investigators plan to continue studying the effects of AD and COVID-19, as well as other neurodegenerative disorders. Additionally, they plan to study the potential to repurpose FDA-approved drugs to treat COVID-19’s long-term effects.

Additional studies have shown that individuals with dementia are twice as likely to contract COVID-19, and those with substance use disorder order are also more likely to get the infection.

Furthermore, approximately 5% of individuals who took Paxlovid for treatment of COVID-19 symptoms experienced rebound infections within a month.

Reference

Risk factor for developing Alzheimer's disease increases by 50-80% in older adults who caught COVID-19. News release. Science Daily. September 13, 2022. Accessed September 26, 2022. https://www.sciencedaily.com/releases/2022/09/220913140850.htm