Patients hospitalized with Covid-19-associated pneumonia were more likely to develop dementia than patients hospitalized with other types of pneumonia, according to a study published March 7 by Open Forum Infectious Diseases, adding to a growing body of research linking Covid-19 to cognitive disorders and brain damage.
A study of data 20,806 patients found that patients hospitalized with non-Covid-19 pneumonia ran a 2.5% risk of developing new-onset dementia following recovery, whereas patients hospitalized with Covid-19 pneumonia ran a 3% risk, an increase of 18.6%, University of Missouri researchers said based on data gathered by health information technology company the Cerner Corporation.
This effect was strongest among people over 70, where risk of dementia was 5% after non-Covid-19 pneumonia and 6.4% after Covid-19 pneumonia, an increase of roughly 28%.
Covid-19 survivors developed a type of dementia tending to impact memory and the ability to carry out daily tasks while leaving language ability and awareness of time and place relatively intact, said lead researcher Dr. Adnan I. Qureshi in a statement Tuesday.
Researchers detected no dementia risk associated with Covid-19 pneumonia for people age 35-70, though the study did suggest a roughly .2% risk of dementia for people under 35 who had Covid-19 pneumonia, compared to a 0% risk for people in that age group who had non-Covid-19 pneumonia.
The median delay between Covid-19 pneumonia and the onset of dementia was 182 days, researchers said.
Surprisingly, cardiovascular diseases and risk factors like cigarette smoking, alcohol use and a history of stroke were more common among patients with non-Covid-19 pneumonia than among patients with Covid-19 pneumonia, researchers found.
Scientists have struggled to untangle Covid-19’s effect on the brain and on cognitive function. A British Medical Journal study found that Covid-19 infection is strongly associated with mental health disorder diagnoses—particularly diagnoses of depression, anxiety and stress disorders like PTSD. Covid-19 is also capable of impacting the structure of the brain, in some cases damaging cells associated with the sense of smell, inflicting permanent smell loss. The mechanism by which the coronavirus alters brain structure is still debated, and neurological smell loss associated with the virus may be a result of symptoms like inflammation, rather than damage done directly by the virus itself. There is also some evidence suggesting a link between Covid-19 and Alzheimer’s disease, though scientists warn that it could be decades before it’s possible to know for sure whether the virus causes Alzheimer’s. Future research should investigate the underlying mechanisms of Covid-19 disease to develop strategies for preventing disabling conditions like dementia, the authors of the Open Forum Infectious Diseases study wrote.
A JAMA Network Open study found that psychiatric disorders may increase the risk of breakthrough infections after vaccination, possibly due to lowered immune function among people with certain psychiatric disorders, which could decrease vaccine effectiveness.
“A Case Of Shrunken Brains: How Covid-19 May Damage Brain Cells” (Forbes)