- A Danish study establishes a link between infections with the coronavirus and the risk of developing diseases such as dementia or Parkinson’s afterwards.
- It has long been known that severe infections can lead to certain secondary diseases.
- However, it is unclear whether the risk of COVID-19 is particularly high, what protection the vaccination offers and which virus variants play a role in such processes.
Has someone to COVID-19 is ill, a higher risk, then a dementia or develop Parkinson’s? A Danish study came to this conclusion.
Federal Minister of Health Karl Lauterbach (SPD) picked up a corresponding report from the Bild newspaper on Twitter and wrote that the connection with Alzheimer’s was “unfortunately not scaremongering”: “It’s good to point out this danger.”
What is the study about?
The researchers analyzed the medical records of around half of the Danish population, which corresponds to around one million people. Around 43,000 of them tested positive for the corona virus during the study period.
It was recorded how many of those suffering from COVID-19 were later diagnosed with Alzheimer’s, Parkinson’s or an autoimmune disease such as multiple sclerosis and how many of these people suffered a stroke or brain hemorrhage. This data was also collected for people who had had the flu and who had had bacterial pneumonia.
What were the results of the study?
The scientists found that people who had previously tested positive for the coronavirus had a higher risk of developing Alzheimer’s and Parkinson’s disease six to twelve months later. They were also more likely to have strokes and cerebral hemorrhages.
However, the researchers also found that the risk of these diseases is similar after influenza and after bacterial pneumonia. Only the risk of stroke was slightly increased after COVID-19 compared to the other diseases.
How is the study to be assessed?
According to Malik Böttcher, general practitioner in Berlin and head of the vaccination center at the Havelhöhe Hospital in Spandau, the significance of the study is “not that great”. The study provides some indications of connections, but no evidence. “Anyone who is younger than 60 years old does not have to worry about the fact that they could develop dementia after COVID-19 because of the study,” he says.
The authors of the study also limit the informative value: It is also conceivable, for example, that some of the people examined already had symptoms of dementia, but this was only diagnosed when they were admitted to the hospital.
But: Conversely, it has also been known for some time that serious infections can lead to secondary diseases. “We experience this in practice, for example, again and again after severe flu outbreaks,” says Böttcher. It is therefore conceivable that this can also happen after an infection with the corona virus – although possibly not more frequently than with other diseases.
What explanation is there for the fact that infections can have such effects?
One explanatory model is the so-called neuroinflammation. This is an inflammation in the central nervous system (neuro = relating to the nervous system), i.e. in the brain. Researchers have long suspected a connection between neuroinflammation and diseases such as Alzheimer’s and Parkinson’s.
How does neuroinflammation occur?
The brain is supplied with oxygen and nutrients by the blood. But there are special filters that ensure that pathogens and immune cells from the rest of the body do not get into the brain. “This protection is also known as the blood-brain barrier,” says Böttcher.
However, this barrier can become permeable and no longer protect the brain as reliably. “We see that, for example, with viral pathogens or bacterial inflammations, which are particularly severe,” says the doctor. This puts certain brain cells, which actually have a protective function, into an alarm state. They then attack certain structures in the brain. It is assumed that this can lead to the development of Alzheimer’s dementia, for example. However, this does not happen suddenly, but over many years.
Can one assume that vaccinations protect against neuroinflammation and thus against Alzheimer’s disease after COVID?
“Vaccination naturally protects against such processes to the extent that it protects against infections,” says Böttcher. “However, we can only be moderately satisfied with the effect of the vaccination at the moment.” An infection is just as common about two months after a booster as in unvaccinated people.
However, the courses are almost always much easier in vaccinated people. “We therefore assume that a vaccination also protects against neuroinflammation to a certain extent because certain immune processes are not further heated up,” says the doctor. However, vaccines that are so closely tailored to the current pathogens that an infection does not occur in the first place are desirable.
What role do different variants of the virus play?
It is not yet known which variants of the corona virus can trigger such processes. “But we see that the phenomenon Long COVID under the omicron variant,” says Böttcher. Compared to the delta variant, it is around 1:20. “We therefore assume that there is less neuroinflammation with omicron,” says the doctor. Also however, there is still a lack of reliable data on this.
What are the early warning signs of dementia?
According to Susanne Saxl-Reisen, spokeswoman for the German Alzheimer Society, one of the early warning signs is when people withdraw from social activities, are no longer able to orientate themselves spatially or temporally, or suffer from memory disorders. If someone suddenly finds themselves unable to find words during a conversation, has difficulties with everyday tasks or suffers from mood swings and behaves differently than usual, these can also be warning signs.
“It is important to talk to a doctor about symptoms that last for a long time,” says Saxl-Reisen. These signs do not always mean that someone is suffering from dementia: “There can be very different causes, for example depression, a malfunction of the thyroid gland or drug interactions.”
Also read: “There is a great deal of desperation” – dementia in younger people
How can you protect yourself?
There is no real protection against dementia. “But there are a number of risk factors that can be influenced,” says the spokeswoman. Everyone can do something to reduce their risk of dementia:
- Be physically and mentally active
- Maintain social contacts and avoid loneliness
- Have high blood pressure and diabetes well controlled
- Correct hearing loss early with a hearing aid
- Do not smoke
- Drink alcohol in moderation
- Avoid being overweight
- Protect your head from injury
However, the greatest risk of dementia cannot be avoided: old age. “While less than two percent of the 65 to 69 year olds are affected, it is more than a third of the over 90 year olds,” says the expert. In addition, women are more likely to be affected by dementia than men. This is largely due to the higher life expectancy of women.
What can therapy look like?
There is currently no cure for dementia. “Depending on the cause, there are limited drug treatment options,” says Saxl-Reisen: If the dementia is related to circulatory disorders, drugs that increase blood circulation are prescribed. Drugs that increase certain neurotransmitters in the brain can also help with some forms of dementia.
Non-drug treatment approaches are also important in dementia. “This includes, for example, occupational therapy, which helps to maintain independence for as long as possible,” says the expert. Memory therapy, physiotherapy, behavioral therapy and other forms of therapy can also be helpful.
In addition, according to the German Alzheimer Society, treating people with respect is crucial: the aim is to accept that people with dementia live in their own world. Apparently crazy behavior should also be taken seriously and you should try to understand it.
About the experts:
Malik Boettcher is a general practitioner and head of the vaccination center at the Havelhöhe Hospital in Spandau. The doctor works for vaccinations both in the vaccination center and in his practice at Kleistpark in Berlin-Schoeneberg.
Susanne Saxl Travel is deputy managing director of the patient organization German Alzheimer Society and responsible for public relations. The organization is committed to improving the lives of people with dementia and supports those affected and their families. She is also committed to better diagnosis and more competent advice on site.
Sources used:
- Pardis Zarifkar et. al.: Frequency of Neurological Diseases After COVID-19, Influenza A/B and Bacterial Pneumonia, in: Frontiers in Neurology, 23. Juni 2022
- Malik Böttcher, general practitioner and head of the vaccination center at the Havelhöhe Hospital in Spandau
- Susanne Saxl-Reisen, deputy managing director and spokeswoman for the German Alzheimer Society
- German Alzheimer Society: The non-drug treatment of dementia (Info sheet 6)
Updated 6/9/2022 at 5:45 p.m
According to “Ärzteblatt.de”, around 1.6 million people in Germany suffer from dementia. Now scientists want to have found out that walking speed can be an early warning sign of the disease. (Image credit: picture alliance / ZB/Britta Pedersen) © ProSiebenSat.1