- Researchers say they’ve discovered that people who have had COVID-19 have a higher risk of developing Parkinson’s, Alzheimer’s, and ischemic stroke.
- Experts say they already knew that COVID-19 can exacerbate the symptoms of Parkinson’s in somebody with the disease.
- They say this new study reiterates the need for people with these conditions to be in as good of overall health as possible.
The scientific community continues to learn more about the widespread effects COVID-19 has on the body.
A study from Denmark published today looking at the health records of more than half of the Danish population found that those who had tested positive for COVID-19 were at an increased risk of being diagnosed with Alzheimer’s disease, Parkinson’s disease, ischemic stroke, and bleeding in the brain.
The study, presented at the 8th European Academy of Neurology (EAN) Congress, included 43,375 individuals with COVID-19 and 876,356 individuals without the disease.
Researchers reported that the people who tested positive had between 2 times and 3 times increased risk of ischemic stroke, particularly in younger people.
They also observed significant increases in the rates of Alzheimer’s and Parkinson’s diagnoses one year after COVID-19 infection.
Dr. Pardis Zarifkar, the lead author of the study and a member of the Department of Neurology at Rigshospitalet hospital in Copenhagen, told Healthline that while previous studies have established an association with neurological syndromes, it was not known whether COVID-19 also influences the incidence of specific neurological diseases and whether it differs from other common respiratory infections.
The increased risk of most neurological diseases was, however, no higher in COVID-19-positive people than in those who had been infected with influenza or bacterial pneumonia.
The association between influenza and Parkinson’s is already established, Zarikar explained, although influenza vaccines have been shown to reduce the risk of Alzheimer’s.
Dr. Rachel Dolhun, the senior vice president of medical communications at the Michael J. Fox Foundation for Parkinson’s Research, said this kind of study can understandably grab attention and raise concerns.
“We know that COVID, like any infection, can temporarily worsen symptoms in people who live with Parkinson’s. We don’t yet know whether COVID can bring on Parkinson’s,” Dolhun told Healthline.
“This study is an important step toward answering that question. Throughout the pandemic, there have been several reports of people developing symptoms of Parkinson’s following COVID infection,” she added.
Many researchers believe that, in these cases, a person likely had Parkinson’s changes in the brain and the infection triggered symptoms, she noted.
“Still, it’s unclear how or why, exactly, this might happen,” Dolhun said.
The study, she added, reemphasizes the need for people with Parkinson’s to remain in good health.
“As scientists work toward better understandings, people can work to keep themselves and their brains as healthy as possible,” Dolhun said.
That recommendation is true for both COVID-19 and the flu season.
“Make sure to wash your hands regularly and stay home if you’re sick. And feel empowered to continue wearing a mask and social distancing if that raises your comfort level,” Dolhun said.
She noted the number of people with Parkinson’s is expected to grow significantly over the coming years.
“Experts estimate cases could double by the year 2040. The main reason: age is the biggest risk factor for Parkinson’s, and our population is aging,” she said.
“You can limit your risk and keep your brain as healthy as possible with regular exercise, a healthy diet, positive social connections, and other simple, daily activities,” she added.
Now that Zarifkar and her team have observed increases in the diagnostic rates of Alzheimer’s and Parkinson’s disease after COVID-19 infection, what comes next?
“The next logical step would be to determine why,” Zarifkar said.
“Is this related to a direct viral invasion? Is it due to inflammatory processes that take place in the body in response to the virus? Or is it due to the fact that patients are being more meticulously investigated after COVID-19 infection?” she said.
She added that while biological mechanisms may account for a subsection of these increases, “We expect that the scientific communities’ focus on COVID-19 survivors has led to earlier diagnoses in some and, thus, potentially, short-term diagnostic inflation. Time will tell.”