December 8, 2023

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Nature: Mild diseases of COVID-19 can also age the brain by 1-10 years?

Nature: Mild diseases of COVID-19 can also age the brain by 1-10 years?


Nature: Mild diseases of COVID-19 can also age the brain by 1-10 years? The truth about the brain shrinking caused by the COVID-19 is…

Since the COVID-19 epidemic, the cumulative number of deaths in the world has exceeded 6 million, and the cumulative number of confirmed cases has exceeded 450 million.

Although omicron is still raging, the mortality rate has been greatly reduced compared to before. Many countries have begun to lift restrictions and choose to coexist with the epidemic.


However, can we really “treat the new coronavirus like the flu virus”? After the death rate, the shadow of the COVID-19 sequelae still hangs over the top of every infected person, fatigue, muscle weakness, sleep disturbance, changes in smell and taste, cognitive function decline…


Even decades later, there will be various retrospective studies reporting that the new coronavirus has far-reaching legacy. For example, people who were infected with the new coronavirus in the past have a sharply increased risk of Alzheimer’s disease in old age.

In fact, there are currently a small number of Studies have shown abnormal levels of amyloid in the brains of severe deaths from COVID-19.


Recently, a study from Oxford University has been controversial, and major media, self-media, and big V are talking about it. The study shows that even mild COVID-19 infection can lead to brain atrophy and cognitive decline.

The study was published on Nature’s official website in the form of an ” Accelerated Article Preview ” so that readers can learn about the relevant research results as soon as possible.


How is the research done, where is the controversy, let’s read this literature together today.


Nature: Mild diseases of COVID-19 can also age the brain by 1-10 years?


The study samples came from a large-scale imaging data collection program carried out by the UK Biobank (UK Biobank) since 2016, just to provide researchers with human brain imaging data before the COVID-19 epidemic.


After the outbreak of the COVID-19, the researchers again performed brain scans on 785 volunteers aged 51-81, including 401 patients with COVID-19 infections and 384 non-COVID-19 infections, and 96% of the infected people had mild symptoms Of the patients, only 15 were hospitalized and 2 were critically ill.


In addition, in order to exclude the influence of other factors on the conclusions of the study, the case group and the control group were matched in terms of age, race, gender, socioeconomic status, time between two brain scans, and pre-epidemic health status.


The results showed that the thickness of gray matter in some brain regions related to smell and memory was reduced in patients with COVID-19 infection, with a loss rate of 0.2%-2%, accompanied by an increase in signs of brain tissue damage. And the older the infected person, the more severe the disease, and the more obvious the brain tissue damage.


Nature: Mild diseases of COVID-19 can also age the brain by 1-10 years?


Although the researchers describe this change as modest (slightly) in the article , if “the gray matter of the brain is being lost at a rate of 0.2%-0.3% per year”, it is indeed “easy” to get “the COVID-19 infection will lead to brain aging” 1-10 years” conclusion.


Next, the Cognitive Function Test (TMT) was performed on the case and control groups , including: connecting Arabic numerals in sequence (1-2-3) , and connecting numbers with corresponding letters (1-A ,2-B) , the test results can provide information such as visual search speed, processing speed, mental flexibility and executive function.


Compared with non-infected patients, infected patients took longer to complete the test, suggesting a decline in cognitive function, consistent with imaging findings of atrophy in the cerebellar cognitive region crus II in infected patients.


Nature: Mild diseases of COVID-19 can also age the brain by 1-10 years?


Finally, the researchers compared whether patients with other types of pneumonia developed similar brain degenerative changes, and it turned out that the brain damage was unique to the new coronavirus, rather than a disease feature shared by pneumonia .


This is the largest and only longitudinal study on brain imaging of patients with COVID-19 pneumonia. Without pre-infection brain imaging data, it’s hard to tell whether the infection is causing the brain to become smaller, or whether people with smaller brains are more susceptible to infection.


But it also has shortcomings. For example, the time point of the second brain imaging acquisition was in April 2021, when the delta virus strain began to circulate in the UK, which means that the results of this study are derived from Alpha, Beta, Gamma strains, Omicron It is not certain that it will have the same result.


Secondly, studies have shown that vaccination can reduce the incidence of sequelae of the COVID-19, and this study did not mention the vaccination status of volunteers , so the question is, whether the whole vaccination can help reduce the brain after infection. symptom?


Most importantly, the degenerative changes in the brain caused by the new coronavirus are mainly the reduction of gray matter in the olfactory system.

When the sense of smell is restored, can these brain structural changes also recover? After all, in previous studies, patients with idiopathic anosmia had significantly increased gray matter volume in olfactory-related areas after olfactory training.

Some scholars also believe that the atrophy of the olfactory cortex is caused by the loss of the sense of smell in patients with the COVID-19, and the lack of external odor stimulation .


Lead researcher Gwenaelle Douaud, a professor at the University of Oxford, UK, also acknowledged that “the brain changes associated with COVID-19 have the potential to subside over time, and the best way to find out is to scan these participants again after a year or two.”


For the masses, we are more concerned about whether the current omicron will cause brain damage, the degree of damage, and whether vaccination can reduce the risk? Before the final result comes out, we can only protect ourselves from infection as much as possible.

The reduction of virus toxicity is not the reason for us to lie down The sequelae brought by the COVID-19 virus deserve our vigilance.






[1]SARS-CoV-2 is associated with changes in brain structure in UK Biobank.

Nature: Mild diseases of COVID-19 can also age the brain by 1-10 years?

(source:internet, reference only)

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