(ORDO NEWS) — At least 22 viral infections have been associated with an increased risk of neurodegenerative diseases, including Alzheimer’s and dementia.
However, scientists suggest that vaccination against these viruses may be a way to reduce this risk.
For the study, US scientists assessed the temporal changes in the performance of approximately 350,000 people who were in FinnGen, a nationwide biobank in Finland.
Specialists have identified patients who have been diagnosed with Alzheimer’s disease, amyotrophic lateral sclerosis, dementia, multiple sclerosis (MS), Parkinson’s disease or vascular dementia.
Once these patients were identified, the researchers determined if any of them had a previous viral infection that led to hospitalization. Patients who were hospitalized for COVID-19 were not included in the study.
Overall, the researchers found 45 significant associations between a previous viral infection and a neurodegenerative disease diagnosis, with some exposures associated with increased risk up to 15 years after the initial infection.
Using cross-sectional data from approximately 106,000 participants over the age of 60 from the British Biobank, the researchers were able to replicate 22 of these associations.
In terms of hazard ratio, viral encephalitis and Alzheimer’s disease were the most associated at 30.72.
“We see in FinnGen that 24 out of 406 cases of viral encephalitis developed Alzheimer’s disease (5.9%); this is higher than the overall prevalence of Alzheimer’s disease in the same population of less than 3%.” the researchers explained.
The disease with which there was the most association was dementia, which turned out to be associated with six different viruses: encephalitis, viral warts, all types of influenza, influenza and pneumonia, viral pneumonia, chickenpox.
In addition, severe cases of influenza were associated with the widest range of risks, while exposure to both influenza and pneumonia was associated with all neurodegenerative diagnoses except multiple sclerosis. Epstein-Barr virus has been most associated with the risk of multiple sclerosis.
In 16 associations, the risk of a neurodegenerative diagnosis was high within a year of infection, and in six associations, the risk of diagnosis was high if the infection occurred 5 to 15 years ago.
“The vast majority of replicated associations involve viruses commonly considered neurotrophic (81%), meaning they can enter the central nervous system via peripheral nerves or cross the blood-brain barrier,” the researchers wrote.
According to them, this suggests that these viruses may increase the risk of neurodegenerative diseases by reducing cognitive reserve (resistance to neurodegeneration and the ability to perform complex mental tasks), promoting inflammation in the brain.
The results of the study show that vaccination has the potential to reduce the risk of neurodegenerative diseases in some people.
However, some doctors believe that there is no pronounced relationship between viral diseases and the risk of developing dementia, because in percentage terms these associations are very small.
—
Online:
Contact us: [email protected]
Our Standards, Terms of Use: Standard Terms And Conditions.