Covid-19 was associated with nervous diseases early on. A large-scale study has now determined that the risk of Alzheimer’s, Parkinson’s and cerebral infarction is significantly increased. But this also applies to other respiratory diseases.
Those who tested positive for Covid-19 have a higher risk of developing nervous diseases such as Alzheimer’s and Parkinson’s – this is the result of a new study from Denmark, for which health data from more than half of the population was analyzed. The research was presented at the Congress of the European Academy of Neurology (EAN).
The researchers looked more closely at data from 919,731 people who had been tested for Covid-19. Of these, 43,375 had received a positive result. And among these patients, the authors found a 3.5-fold increased risk of developing Alzheimer’s. The risk for Parkinson’s was 2.6 times higher and for a cerebral infarction 2.7 times higher. The risk of suffering a cerebral hemorrhage was even increased almost 5-fold.
The study analyzed inpatients and outpatients in Denmark between February 2020 and November 2021, as well as influenza patients from the corresponding period before the pandemic. The researchers used statistical methods to calculate the relative risk.
“After the outbreak of the Covid-19 pandemic, the exact nature and evolution of the effects of Covid-19 on neurological diseases remained unclear for more than two years,” said Pardis Zarifkar from Rigshospitalet in Copenhagen and lead author of the study, according to a statement. According to Zarifkar, earlier studies had found a connection with neurological syndromes. However, it remained unclear whether Covid-19 also affects the frequency of certain neurological diseases – and whether it differs from other respiratory infections.
It is now clear that the risk of nervous diseases is higher for Covid 19 patients than for those who did not have it – but not higher than for people who have been diagnosed with the flu or another respiratory disease.
However, there is apparently one difference: Covid-19 patients had a 1.7-fold increased risk of a cerebral infarction compared to over 80-year-old inpatients with flu or bacterial pneumonia. However, the frequency of other nervous diseases such as multiple sclerosis, myasthenia gravis, Guillain-Barré syndrome and narcolepsy did not increase after Covid-19, flu or pneumonia.
