Not Causation, But Correlation
Researchers from the US National Institutes of Health have discovered a correlation between viral illnesses and an increased chance of developing neurodegenerative diseases. In other words, it has found numerous associations between common viruses like the flu and devastating neurodegenerative disorders.
The findings expand on previous research linking individual viruses to neurological diseases. However, experts caution that the study, which relied on electronic medical records (data mining) rather than biological samples, merely describes correlations and doesn’t prove causation. Although the study found potential links between viral exposures and neurodegenerative disease risk, more future researchs will have to confirm causality or not.
Above all, researchers from the NIH have found a correlation between having a viral illness earlier in life and an increased risk of developing neurodegenerative diseases. A neurodegenerative disease affects the body’s central nervous system, including the brain. Such conditions can impact certain body functions such as movement, balance, speaking, thinking, and memory.
Types Of Neurodegenerative Diseases Related To Viral Illnesses:
● Dementia, including Alzheimer’s disease.
● Parkinson’s disease.
● Huntington’s disease.
● Multiple Sclerosis (MS).
● Amyotrophic Lateral Sclerosis (ALS).
● Spinal Muscular Atrophy.
● Lewy Body Dementia.
Researchers have more frequently linked influenza that progressed to pneumonia with neurodegenerative diseases. It showed a positive association with all of the diseases except MS. Dementia was the brain malady most commonly associated with viral infections. Medical experts have linked it with flu (with or without pneumonia) and viral encephalitis. There are many different viruses that can cause this rare infection of the brain.
But the caveats and weaknesses of the study are many, experts say. Most prominently, the pairings are only associations; they do not prove the viruses are causing the brain diseases. There may be genetic reasons someone is more susceptible to both viruses and Parkinson’s, for example. And other environmental exposures likely also play a role in causing neurodegenerative diseases.
“There’s a great deal of work that needs to be done to try to link viral exposure and risk for neurodegenerative diseases mechanistically,” concedes senior author Andrew Singleton, who heads NIH’s Center for Alzheimer’s and Related Dementias.