COVID-19 affects the brain in various ways. A recent comprehensive study indicated that COVID-19 virus infection increases the risk of neurodegenerative diseases such as Alzheimer’s and leads to long-term cognitive impairment.
Currently, over 55 million people are living with dementia worldwide, with nearly 10 million new cases each year. Alzheimer’s disease is the most common form of dementia, accounting for approximately 60 percent to 70 percent of dementia cases.
Alzheimer’s disease patients often experience various complications, with pneumonia infection being one of the leading causes of death.
Postmortem analysis of the brains of individuals infected with COVID-19 revealed that gliosis and immune cell accumulation are associated with axonal damage and blood-brain barrier disruption and leakage. The infection leads to endothelial damage and increased capillary permeability, thereby contributing to inflammatory diseases of the central nervous system, such as Alzheimer’s disease.
Cytokine storm is considered a major contributing factor to the neurological complications of COVID-19. Patients with severe COVID-19 exhibit a heightened inflammatory immune response, leading to the release of pro-inflammatory cytokines, including IL-6 and IL-1-beta. Elevated levels of these inflammatory markers are associated with impaired neurogenesis and hippocampal-dependent memory.
Additionally, elevated plasma biomarkers of glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) have been observed in moderate to severe COVID-19 patients, indicating astrocytic and neuronal damage. Some neurological manifestations of COVID-19 may, in part, be attributed to hippocampal injury and neuronal death, potentially resulting in long-term neurological sequelae. This includes cognitive impairment in patients with long COVID.
Higher Risk of Alzheimer’s Disease in Older COVID-19 Patients
A large-scale retrospective cohort study conducted in the United States in 2022 found that the risk of developing Alzheimer’s disease significantly increases in older adults within the year following a COVID-19 infection.Before propensity-score matching, the overall risk of new Alzheimer’s disease diagnoses in the COVID-19 cohort was 0.68 percent, compared to 0.35 percent in the non-COVID-19 cohort. After propensity-score matching, the risk of new Alzheimer’s disease diagnoses in the COVID-19 cohort increased by 69 percent compared to the non-COVID-19 cohort. When segmented by age and gender, individuals aged 85 and older and females had the highest risk of Alzheimer’s disease, with an increase of 89 percent and 82 percent, respectively.
How Can We Prevent Alzheimer’s Disease?
Professor Hideki Wada, a psychology professor at the International University of Health and Welfare and an eminent psychiatric expert in Japan, stated that as the population ages and life expectancy increases, the number of individuals suffering from cognitive impairment disorders is expected to rise. Similar to many other diseases, early detection and early intervention are crucial for the treatment of dementia.Brain stimulation is essential to prevent dementia, and socialization is not the only method to stimulate the brain. There are many ways to prevent Alzheimer’s disease, and Mr. Wada’s top recommendation is learning.
