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.