Neurodegenerative diseases that cause dementia increase the risk of death from infection with severe COVID-19. For patients with Alzheimer’s disease, the risk is tripled. A study conducted in Brazil by researchers at the University of São Paulo (USP) and the Butantan Institute in collaboration with colleagues at the Federal University of Rio de Janeiro (UFRJ) found that it could be six times higher for people over the age of 80.
Articles on this study, supported by FAPESP, can be found below. Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association..
"All causes of dementia were found to be COVID-19 severity and risk factors for death, and these risks were found to be more pronounced in patients with Alzheimer’s disease. “
Sérgio Verjovski-Almeida, Principal Researcher of the Project and Professor of the USP Institute of Chemistry
Dementia, along with other comorbidities such as cardiovascular and respiratory illness, hypertension, diabetes, obesity and cancer, has already been identified as a risk factor for COVID-19. One of the reasons is age. People with dementia tend to be older and many live in long-term care facilities at high risk of infection or viral infection.
However, it reveals whether people with dementia-causing neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease are at increased risk of developing severe forms of COVID-19 or dying from infection with the new coronavirus. No research has been done so far. And so far, no one has tried to find out if old age increases this risk.
To answer these questions, researchers surveyed data on positive diagnosis, hospitalization, and death with COVID-19 in a cohort of 12,863 patients aged 65 years and older who tested positive or negative for SARS-CoV-2. Did. The data was included in the UK Biobank from March to August 2020. UK Biobank is a biomedical database containing genetic and health information collected from 500,000 patients since 2006.
Of the approximately 13,000 subjects, 1,167 tested positive for COVID-19 by RT-PCR. To control the potential for bias associated with untested young asymptomatic individuals, researchers excluded subjects aged 49-65 and divided them into three age groups, including only subjects aged 66 and older. Hierarchical: 66-74 (6,182), 75-79 (4,867), and 80-86 (1,814).
“The advantage of using UK Biobank clinical data is that the records refer to all existing illnesses and the detailed amount of whether the patient tested positive and whether he was hospitalized and died of COVID-19. “Includes,” Verjovski-Almeida explained. “This assesses all causes of dementia, especially risk factors associated with infection, severity, and death from the disease, including Alzheimer’s disease and Parkinson’s disease.” I was able to do.”
Statistical analysis has shown that all causes of dementia, especially Alzheimer’s disease, are risk factors for illness severity and death in hospitalized patients, regardless of age.
Alzheimer’s disease, in particular, did not increase the risk of hospitalization compared to chronic comorbidities. However, after admission, patients with Alzheimer’s disease were three times more likely to develop severe COVID-19 or die of the disease than patients without Alzheimer’s disease. Patients with Alzheimer’s disease over the age of 80 were at 6 times higher risk than patients in the younger age group.
“Several factors that have not yet been identified increase the likelihood that people with Alzheimer’s disease will progress to severe COVID-19 and die of viral disease,” Verjovski said. “Our findings show that special attention should be paid to these patients on admission.”
A possible explanation for the observed results is the ability of a defective immune response due to chronic inflammatory conditions or aging of the immune system (immune aging) to increase the vulnerability of these patients and initiate an effective response to viral infections. Is that it can reduce.
Another hypothesis is that Alzheimer’s disease alters the permeability of the blood-brain barrier, making it more susceptible to central nervous system infections.
Recent studies have shown that SARS-CoV-2 invades the central nervous system through the olfactory mucosa, and the presence of the virus in this area triggers a localized inflammatory immune response. In the same study, the virus was detected in the brainstem, which constitutes the major cardiovascular and respiratory control centers, and central nervous system infections could mediate or exacerbate respiratory and cardiovascular problems in COVID-19 patients. There is sex.
“Analyzing the genomes of these patients, also available from UK Biobank, which genes are mutated may be involved in severe COVID-19 and increased risk of death in patients with Alzheimer’s disease. “Verjovski-Almeida said.
Tahira, AC, Et al. (2021) Dementia is an age-independent risk factor for COVID-19 inpatients’ severity and death. Alzheimer’s disease and dementia. doi.org/10.1002/alz.12352..