Study Links Viruses With Alzheimer
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by
Ree Webster
Study of 500,000 Medical Records Links Viruses With Alzheimer’s Again And Again
A new study analyzing approx. 500,000 medical records suggests that severe viral infections like encephalitis and pneumonia can increase the risk of neurodegenerative diseases like Parkinson’s and Alzheimer’s.
The study, involving approx. 450,000 people, showed 22 connections between viral infections and neurodegenerative conditions. For example, patients with encephalitis were 31 times more likely to develop Alzheimer’s, and those with pneumonia due to the flu also appeared to be more susceptible to Alzheimer’s, as well as dementia, Parkinson’s disease, and amyotrophic lateral sclerosis (ALS). Furthermore, intestinal infections, meningitis, and the varicella-zoster virus responsible for causing shingles were all implicated in the development of several neurodegenerative diseases.
The potential risks are not short-lived, instead studies revealed that the impact of viral infections on the brain can persist for up to 15 years, and this appeared to be true for the majority of viruses as approx. Eighty percent of those implicated in brain diseases were considered ‘neurotrophic’, which means they could cross the blood-brain barrier. The findings are hoped to pave the way for the creation of vaccines, which could, in theory, be developed for a number of these common conditions. The researchers wrote in their paper;
"Strikingly, vaccines are currently available for some of these viruses, including influenza, shingles (varicella-zoster), and pneumonia,
"Although vaccines do not prevent all cases of illness, they are known to dramatically reduce hospitalization rates. This evidence suggests that vaccination may mitigate some risk of developing neurodegenerative disease."
In 2022, a similar study of over 10 million people linked the Epstein-Barr virus with a dramatically increased risk of developing multiple sclerosis. This set off a spark in the researcher’s minds, who accredited the findings to be their main inspiration. Senior author of the study, Michael Nalls, a neurogeneticist at the National Institute on Aging in the US, said:
“After reading [this] study, we realized that for years scientists had been searching – one-by-one – for links between an individual neurodegenerative disorder and a specific virus,”
“That’s when we decided to try a different, more data science-based approach. By using medical records, we could search for all possible links in one shot systematically.”
Researchers first analyzed the medical records of 35,000 individuals with six different types of neurodegenerative diseases, then compared this with a group of 310,000 controls who did not have any brain disease.
The results discovered 45 links between viral exposure and neurodegenerative diseases. A subsequent analysis of 100,000 medical records from the UK Biobank narrowed the findings to confirm 22 links.
Co-author Andrew Singleton, a neurogeneticist and director of the Center for Alzheimer’s and Related Dementias, said:
"Neurodegenerative disorders are a collection of diseases for which there are very few effective treatments and many risk factors…
"Our results support the idea that viral infections and related inflammation in the nervous system may be common – and possibly avoidable – risk factors for these types of disorders."
Alzheimer’s disease is caused by a combination of genetic, environmental, and lifestyle factors that lead to the progressive degeneration of brain cells.
Age is the most significant risk factor, but family history, specific genes (like APOE4), and conditions like heart disease, diabetes, and head injuries also contribute. Chronic inflammation, oxidative stress, and an imbalance in brain chemicals can further exacerbate the disease. While the exact cause remains unclear, it is widely suspected that Alzheimer’s results from these combined factors, disrupting memory, cognition, and behavior.
Current treatments for Alzheimer’s aim to alleviate symptoms and slow disease progression but, unfortunately, cannot cure or reverse it. Medications such as cholinesterase inhibitors (donepezil, rivastigmine, and galantamine) improve communication between brain cells by increasing acetylcholine levels. Another drug, memantine, regulates glutamate activity, reducing symptoms in moderate to severe cases.
In recent years, anti-amyloid therapies like aducanumab and lecanemab have been developed to target beta-amyloid plaques, offering hope for slowing cognitive decline. Non-drug approaches, including cognitive therapy, physical exercise, and social engagement, also play a key role in managing symptoms and maintaining quality of life. While these treatments provide temporary relief, they are most effective with a comprehensive care plan tailored to individual needs.
With no effect treatment or cure, any related data/information is welcome since it could potentially unlock the necessary clues needed to help develop much-needed treatments. The recent findings show promise, as they appear to have found a link between viruses and an increased risk of developing PACS1. As we all know, preventative measures are always better than a cure, and uncovering the mechanisms behind these conditions is a promising step in discovering how to prevent these conditions from occurring in the first place.
