For several years, scientists have been working on the origin of Alzheimer’s disease and have been digging the trail of a viral origin. According to these experts, it is a viral infection that would first cause the accumulation in the brain of amyloid plaques, associated with Alzheimer’s disease.
A new study from Case Western Reserve University in Cleveland (United States) will reinforce this line of research. This study, which covers more than 6 million people over the age of 65, reveals that seniors who have been infected with the covid-19 virus have a 50 to 80% higher risk of developing Alzheimer’s disease within a year of infection. The highest risk is found in women over 85 years of age.
A link between viral infection and Alzheimer’s disease
“Two things considered important in the development of Alzheimer’s disease are previous infections, especially viral infections, and inflammation,” said study co-author Prof. Pamela Davis. “Given that covid infection has been associated with central nervous system abnormalities, including inflammation, we wanted to test whether the virus could lead to an increase in Alzheimer’s diagnoses.”
The researchers therefore analyzed the anonymous electronic health records of 6.2 million adults aged 65 and over in the United States, without any diagnosis of Alzheimer’s disease and who had been treated between February 2020 and May 2021. They then divided into two groups: those who had had covid (400,000 people in total) and those who had not. Which allowed them to find that patients who had had covid were considerably more likely to develop Alzheimer’s disease in the year following their infection.
“If this increase in new diagnoses of Alzheimer’s disease continues, the wave of patients suffering from a currently incurable disease will be significant in the years to come” insists Pre Davis. “We thought we had reversed the trend by decreasing general risk factors such as hypertension, heart disease, obesity and a sedentary lifestyle. This is likely to be upset by the impact of covid on disability future”.
Source : Association of covid-19 with New Onset Alzheimer’s diseaseJournal of Alzheimer disease, September 2022
