The 20 million Americans suffering from long Covid may be more likely to develop dementia, a study suggests.
Long Covid is a chronic condition lasting for at least three months after a Covid infection. It comes with a constellation of often dismissed symptoms, including debilitating fatigue, brain fog, shortness of breath and pain.
Despite recent surveys showing eight percent of US adults are living with long Covid, the condition is still poorly understood, and researchers are racing to discover the long-term consequences.
Now, researchers in New York City looked at more than 80 people with long Covid and compared them to healthy adults and adults who had Covid and recovered normally.
Using blood tests and MRI scans, the team found patients with long Covid had a 10 percent larger choroid plexus (CP), a network of blood vessels lined by cells that produce cerebrospinal fluid (CSF). CSF is a clear fluid that removes waste from and provides immune support for the nervous system.
The CP regulates inflammation and waste clearance in the brain, and the team points to past studies that show Covid can damage cells lining CP blood vessels.
Along with larger CP, the team also found having a larger CP was linked to blood-based biomarkers showing the progression of Alzheimer’s disease, the most common form of dementia, and that participants with larger CPs performed two percent worse on cognitive tests.
The researchers suggested long Covid may damage the CP and lead to a higher risk of cognitive decline and Alzheimer’s disease.
Researchers in New York City suggested long Covid, suffered by 20 million Americans, may increase the risk of developing Alzheimer’s disease (stock image)
Dr Yulin Ge, senior study author and a professor in the Department of Radiology at the NYU Grossman School of Medicine, said: ‘Our work suggests that long-term immune reactions caused in some cases after an initial COVID infection may come with swelling that damages a critical brain barrier in the choroid plexus.
‘Physical, molecular, and clinical evidence suggests that a larger CP may be an early warning sign of future Alzheimer’s-like cognitive decline.’
The findings come as about 7 million Americans age 65 and older are living with Alzheimer’s disease, with that figure set to nearly double by 2050.
The new study, published Tuesday in the journal Alzheimer’s and Dementia, looked at 86 people with long Covid, 67 who had Covid but recovered normally and 26 who never had the virus and who were otherwise healthy from the NYU Langone health system.
People in the long Covid group were 61 years old on average, while those in the other two groups had an average age of 72.
Long Covid patients were also more likely to have a higher body mass index (BMI), smoke, drink alcohol and be diagnosed with high blood pressure and diabetes.
The team took blood samples to look at Alzheimer’s biomarkers and MRI scans to evaluate brain structure.
They found based on blood tests, people in the long Covid group had larger amounts of proteins associated with Alzheimer’s disease such as p-tau217 (phosphorylated tau 217).
Tracey Thompson, a long Covid sufferer, told the Daily Mail her symptoms were so severe that she considered assisted suicide. She is pictured above in the hospital in March 2022, after contracting Covid in March 2020
Kirsty Huxter, shown with husband David before catching Covid, said the symptoms from long Covid were so severe that she was left bedbound
This group also had CP volumes about 10 percent larger than healthy controls, suggesting long Covid lead to inflammation that thickened blood vessels in the CP and lead to Alzheimer’s-associated brain damage. The team referred to this as ‘vascular remodeling.’
They also suggested inflammation caused by long Covid hinders blood flow in the brain, reducing the production of CSF and leading to waste buildup.
Additionally, patients with larger CPs performed about two percent worse on a standard 30-point screening test, the Mini-Mental State Exam, which records changes in memory and attention.
Dr Thomas Wisniewski, senior study author and director of the Center for Cognitive Neurology at NYU Langone Health, said: ‘Our next step is to follow these patients over time to see if the brain changes we identified can predict who will develop long-term cognitive issues.
‘A larger, long-term study will be needed to clarify whether these CP alterations are a cause or a consequence of the neurological symptoms, which promises to better focus treatment design efforts.’
