A study from Denmark caused a stir in the media. “Several most common nervous disorders: according to a study, COVID-19 increases the risk of Alzheimer’s”, headlines the German television station ntv.
German Federal Health Minister Karl Lauterbach also tweeted about the study’s findings “Unfortunately, don’t panic.” All of this isn’t entirely wrong, but a look at the study shows there’s no reason to panic.
The researchers looked at the health records of nearly three million Danes for various neurological diseases after COVID-19 infection.
But that’s not all: the scientists also tested in people with influenza and bacterial pneumonia whether they were at an increased risk of developing Alzheimer’s and Parkinson’s disease or suffering a stroke as a result.
The result: Yes, about six to 12 months after a COVID-19 infection, the risk of developing Alzheimer’s dementia or Parkinson’s syndrome is increased. However, the risk is just as high after another respiratory illness such as the flu or bacterial pneumonia.
The only exceptions are stroke and thrombosis – the risk that this actually increases for people after a COVID infection compared to other respiratory diseases.
For those who develop Alzheimer’s after COVID-19, it’s obviously not very reassuring that it could have happened the same way after the flu.
Is the fear of Alzheimer’s justified?
So should we be afraid of getting a disease like Alzheimer’s after a COVID infection?
“I don’t think you can derive it from this study,” says Peter Berlit, general secretary of the German Neurology Society. “This is a population-based statistical study that is not suitable for demonstrating a causal relationship between a COVID-19 infection and the onset of Alzheimer’s or Parkinson’s disease. The study methodology does not provide this.”
In other words, the Danish study does not prove that corona infection is actually the cause of Alzheimer’s disease.
The infections themselves increase the risk of Alzheimer’s
Because, according to the study, the risk of neurodegenerative diseases like Alzheimer’s and Parkinson’s after a coronary infection is no higher than that of other respiratory diseases, the infection itself is more likely to increase the risk. “It’s not really new,” says neurologist Berlit.
“We know that dementia, one form of which is Alzheimer’s, is particularly common after special life events,” says Berlit. This also includes a severe infection, which can be accompanied by a hospital stay.
“It appears that infections cause Alzheimer’s decipherment,” Berlit says. “There were probably symptoms already that had been well compensated up to then.”
However, the situation is different in the case of stroke and thrombosis. “The risk actually increased specifically with COVID-19,” says Berlit, thus confirming the study results from Denmark.
COVID-19 infection leads to a so-called coagulopathy, a blood clotting disorder, which in the case of COVID-19 is associated with increased blood clotting. This promotes strokes, heart attacks, pulmonary embolism, and thrombosis, even one year after infection.
Coronavirus vaccination can reduce the risk of all of these complications. While it does not protect against SARS-CoV-2 infection, it does protect against severe courses that require hospitalization.
The risk of long-term COVID complaints is also reduced by vaccination. “These disorders also include these neurological manifestations,” says Peter Berlit, meaning memory disorders, which may be an early symptom of Alzheimer’s, for example.
However, according to one study, vaccination is less effective than hoped when it comes to preventing long-term COVID – the risk only decreases by about 15 percent.
According to one study, vaccination against the flu also reduces the risk of developing Alzheimer’s by 40% in the four years following the peak.
Anyone who is still afraid of developing Alzheimer’s can do a few things on their own: no smoking, low alcohol, healthy eating, and exercise.
“New data has shown that it is enough for older people over the age of 65 to walk briskly for half an hour a day,” Berlit says. This not only reduces the risk of heart attack and stroke, but also dementia.