Is it true that COVID-19 infection can cause brain atrophy?

True points:

1. Brain atrophy is a normal human aging phenomenon, even if not infected with the new crown, human beings will naturally occur brain atrophy. Studies have shown that brain atrophy occurs "at an accelerated" rate in people infected with covid-19, and this phenomenon has been observed even in mild patients.

2. Some diseases other than the new crown, such as diabetes mellitus in middle age, are also associated with the accelerated appearance of brain atrophy.

3. We must understand the harm of the new crown virus infection, but we must not exaggerate its harm and be too afraid of the virus.

Verifier: A section of Ginger 丨 Associate Professor of Research in the Department of Pathology and Experimental Medicine, University of Pennsylvania School of Medicine

It has been more than 2 years since the outbreak of the new crown epidemic, and more and more people are beginning to worry about the sequelae after the new crown infection. Recently, there are studies that the new crown virus may cause brain atrophy, what is going on?

First, there are indeed people infected with the new crown virus who have "brain atrophy"

The claim that COVID-19 infections cause brain atrophy stems from a recent study published in the journal Nature.

In the Uk's Biobank, researchers identified 785 cases as study subjects. The results of at least two brain scans are available for analysis in these cases, with a gap of about 3 years. The cases were aged between 51 and 81 years, of which 401 were infected with the new crown virus, and the infection time was between two brain scans, averaging 141 days from the second scan. Most of the infected people are mild.

Comparative studies have found that the reduction in gray matter and tissue damage in the brain of people infected with the new crown virus are greater than the natural occurrence of uninfected people. Comparing the two brain scans, COVID-19 patients lost an additional 0.2%-2% of their brain gray matter, and in the brain areas associated with smell, there was tissue damage. Not only that, but tests of cognitive function showed that the cognitive decline in those infected with COVID-19 was also more severe than in the control group.

Based on the findings, the researchers believe that the coronavirus may cause brain atrophy and that even in mild patients, the brain can be damaged.

Note that this is just a "possibility". Due to the limitations of the study, the study could not indicate whether the brain atrophy in people infected with COVID-19 was caused by infection.

A more plausible formulation is that COVID-19 infection "may" accelerate brain atrophy.

During the aging process of the human body, the brain loses a small amount of brain tissue, which is a normal phenomenon. In this study, brain atrophy was also observed in the control group (i.e., those who were not infected with COVID-19). In contrast, the brain atrophy of COVID-19 infected people is more severe, losing an additional 0.2% to 2% of their brain tissue.

What is the concept of this additional loss? In general, during aging, the brain loses 0.2% of its brain volume each year. Therefore, the loss of brain capacity of people infected with new crown is equivalent to aging for more than one year.

Strictly speaking, of course, the study also doesn't rule out the possibility that people who are more susceptible to COVID-19 and develop symptoms after infection may be more likely to develop brain atrophy.

What is the case? More research is needed to illustrate. At the very least, patients in the above study should be continued with a third brain scan to compare whether there was a gap in brain atrophy between the two groups over a longer period of time.

Second, is it possible that all people infected with the new crown virus will have "brain atrophy"?

Everyone is more concerned about such a question: if brain atrophy is a sequelae of the new crown infection, how many people will have brain atrophy?

As mentioned earlier, brain atrophy is a normal human aging process, and brain atrophy will occur even if it is not infected with the new crown virus.

Because of this, all people infected with the new crown virus will naturally have brain atrophy. It's like all people infected with the virus can't end up immortal.

If you don't understand logical analysis and only listen to the conclusions, you may feel a little scary. If a certain percentage of people do not have brain atrophy after infection, can't it be shown that the new crown infection can reverse brain atrophy?

In fact, such a "reversal" is impossible, and the brain atrophy of infected people is inevitable, because it will occur naturally.

The real question to ask is: How many PEOPLE with COVID-19 will "accelerate" brain atrophy? This study does not give an answer.

It should be pointed out that the subject of the study, the time of infection with the new crown virus between March 2020 and April 2021, is not infected with the current Omiljung variant.

Studies have shown that the symptoms of the Omikejung variant are different after infection compared to the previous strain, manifested by worsening infection of the upper respiratory tract and reduced damage to the lower respiratory tract (including the lungs). Even if previous strain infections have accelerated brain atrophy, we cannot make any inferences about the Ormicoreon strain and brain atrophy until there are no results.

Third, patients with certain diseases, "brain atrophy" will be more obvious

Because brain atrophy is a natural aging process, many diseases will accelerate the aging of the human body, which will accelerate brain atrophy.

For example, studies have shown that middle-aged patients with diabetes have a 4% reduction in brain hippocampal volume and 2.9% reduction in whole brain volume compared to people who have never had diabetes. It should be clearly pointed out that this phenomenon is only related to diabetes mellitus in middle age, and if the onset is already old age, the acceleration of brain atrophy cannot be seen.

Therefore, even if the new crown virus is completely gone, as long as there are other diseases, there will still be the problem of "brain atrophy" accelerating.

The new crown virus is a virus that will bring large-scale infectious diseases, and in the face of the virus, we can't completely lie flat! Regardless of whether an infection causes brain atrophy or not, we should try to avoid it.

However, we should not exaggerate the harm of the virus, because the fight against the epidemic also comes at a price. The fear of the virus should not ignore the secondary problems brought about by the fight against the epidemic.

This article was edited by Ambergchen

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