{"id":1052,"date":"2022-03-21T20:59:18","date_gmt":"2022-03-21T20:59:18","guid":{"rendered":"https:\/\/linksus.net\/could-covid-19-increase-the-risk-of-dementia-medical-news-today\/"},"modified":"2022-03-21T20:59:18","modified_gmt":"2022-03-21T20:59:18","slug":"could-covid-19-increase-the-risk-of-dementia-medical-news-today","status":"publish","type":"post","link":"https:\/\/linksus2.linksus.net\/index.php\/2022\/03\/21\/could-covid-19-increase-the-risk-of-dementia-medical-news-today\/","title":{"rendered":"Could COVID-19 increase the risk of dementia? – Medical News Today"},"content":{"rendered":"

For most, COVID-19 causes a few days of mild to moderate symptoms, but others feel the effects for months. Some of these effects are neurological, leading scientists to ask whether COVID-19 could increase the risk of dementia. Medical News Today looked at the evidence and spoke with experts to find out the latest views.
Since the start of the COVID-19 pandemic, more than 425 million<\/a> SARS-CoV-2 infections have been confirmed worldwide. Globally, almost 6 million<\/a> people have died from, or with, the infection. <\/p>\n

For most, when SARS-CoV-2 infection leads to COVID-19, the symptoms are mild to moderate. But for some, symptoms of the illness are prolonged.
Experts<\/a><\/hl-trusted-source> have described this issue, long COVID<\/a>, as \u201cnot recovering [for] several weeks or months following the start of symptoms that were suggestive of COVID, whether you were tested or not.\u201d
Symptoms of long COVID vary, but some are common COVID-19 symptoms, such as fatigue<\/a>, shortness of breath, a cough, and joint pain.
Other respiratory virus infections have been associated with neurological and psychiatric after-effects. The authors of one review<\/a><\/hl-trusted-source> observe that \u201cNumerous respiratory viruses can infect the cells of the peripheral and central nervous systems, elicit inflammatory cascades, and directly and indirectly cause various neurologic manifestations.\u201d
And it seems that COVID-19 is no exception, with many people reporting neurological symptoms<\/a> after SARS-CoV-2 infections. These symptoms may include:
Experts are now investigating how COVID-19 might affect neurocognitive<\/a> function and whether it may increase dementia risk.
SARS-CoV-2 usually gains access to the body via droplets that enter the nose or mouth. From there, the virus moves to the throat. It can then travel to the lungs and other organs, and, various studies<\/a> suggest, may enter the nervous system.
The blood-brain barrier<\/a> stops most viruses from entering the brain. So some studies<\/a> have investigated whether the neurological effects of COVID-19 stem from either a viral invasion of the central nervous system or the systemic effects<\/a><\/hl-trusted-source> of the infection.<\/strong>
One review<\/a> suggests that both may occur in parallel. In severe infections, oxygen deprivation and a cytokine<\/a><\/hl-trusted-source> storm may damage<\/a><\/hl-trusted-source> the blood-brain barrier and allow SARS-CoV-2 to enter the brain.
Another review<\/a><\/hl-trusted-source> backs this up, suggesting that SARS-CoV-2 may disrupt the blood-brain barrier or infect the peripheral neurons, then enter the central nervous system.
Prof. Harris Gelbard<\/a>, director of the Center for Neurotherapeutics Discovery at the University of Rochester Medical Center, told Medical News Today<\/em>:
\u201cA recent cerebrospinal fluid study<\/a><\/hl-trusted-source> suggests that patients with COVID-19 infection have blood-cerebrospinal fluid barrier dysfunction, with pathology occurring in endothelial cells that line blood vessels in the blood-brain barrier. While this study did not demonstrate evidence for the presence of SARS-CoV-2 in any of the cerebrospinal fluid samples, all patients in this study had PCR-proven<\/a> COVID-19.\u201d
Evidence is growing that COVID-19 can cause neurological damage. One 2020 review<\/a><\/hl-trusted-source> observed that \u201cCOVID-19 is also anticipated to take a toll on the nervous system in the long term.\u201d
Another<\/a><\/hl-trusted-source> asserts that \u201cRespiratory virus neurotropism<\/a><\/hl-trusted-source> and collateral injury due to concurrent inflammatory cascades result in various neurologic pathologies, including Guillain-Barr\u00e9 syndrome<\/a>, encephalopathy<\/a>, encephalitis<\/a>, ischemic stroke<\/a>, intracerebral hemorrhage<\/a>, and seizures<\/a>.\u201d
Some research has suggested that SARS-CoV-2 might invade the nervous system in the same way that it invades other cells, via agiotensin-converting enzyme 2 (ACE2)<\/a> receptors. <\/p>\n

However, only certain cells<\/a> in the nervous system have these receptors. Among them are excitatory and inhibitory neurons and other types of cells, such as astrocytes<\/a>, oligodendrocytes<\/a>, and endothelial cells.
One review<\/a> points out that that ACE2 receptors are expressed in small blood vessels in the brain, which could provide a potential entry route for SARS-CoV-2 into the brain.<\/strong>
Prof. Gelbard emphasized that the evidence so far<\/a> of how SARS-CoV-2 might enter the central nervous system is not conclusive: \u201cThe pathologic evidence for direct infection of neural cell types, particularly neurons, remain[s] equivocal at best. Despite survey studies of neuronal expression of ACE2 receptors from brain transcriptome databases, [\u2026] the correlative neuropathology from postmortem human cases is scant.\u201d
Whether or not the virus invades the central nervous system, it is clear that SARS-CoV-2 infection can lead to cognitive dysfunction<\/a> that may last for months or even years after the acute phase of COVID-19.
Many people who are hospitalized with COVID-19 have inflammatory complications, which can affect the nervous system. One study<\/a> has reported that these patients experience delirium, reduced consciousness, stroke, and other encephalopathies<\/a><\/hl-trusted-source> following SARS-CoV-2 infection.
In this study, the researchers found that the degree of inflammation<\/a> was correlated with the severity of COVID-19 symptoms and an increase in pro-inflammatory cytokines.<\/p>\n

Prof. Gelbard, who was not involved in this study, explains how experts interpret the findings:
\u201cOur collective view of this is that SARS-CoV-2 infection\/COVID-19 impacts elderly patients with underlying neurovascular disease, whether it is from cerebrovascular disease, subclinical Alzheimer\u2019s disease, Parkinson\u2019s disease or other neurodegenerative disease, by creating a pro-inflammatory central nervous system milieu that is permissive for cognitive impairment, either manifesting as acute delirium or delirium superimposed on dementia.\u201d
Studies<\/a><\/hl-trusted-source> have shown that people with dementia have increased morbidity and mortality from COVID-19. Many have comorbidities<\/a><\/hl-trusted-source> associated with poor COVID-19 outcome, such as cardiovascular disease, diabetes, hypertension<\/a>, and obesity<\/a>.
Dr. Heather Snyder<\/a>, Alzheimer\u2019s Association\u2019s vice president of medical and scientific relations, told MNT<\/em>:
\u201cThe factors causing or contributing to dementia, including hypertension and diabetes, may be what make individuals with dementia more vulnerable to contracting COVID-19. [\u2026] Research<\/a><\/hl-trusted-source> published in February 2021 in Alzheimer\u2019s & Dementia: The Journal of the Alzheimer\u2019s Association<\/em> found that risk of contracting COVID-19 was twice as high for people living with dementia than those without it.\u201d
People with dementia are more at risk of COVID-19 \u2014 but might the disease worsen existing dementia or cause the development of dementia?
It may be that for people with dementia, SARS-CoV-2 can more easily enter the brain, as the blood-brain barrier is damaged<\/a><\/hl-trusted-source>. This might explain worsening symptoms reported<\/a> in people with dementia after COVID-19. <\/p>\n

One study<\/a><\/hl-trusted-source> states: \u201cThere is evidence for a bidirectional relationship between viral infections and dementia: People with dementia have an increased risk for infection, while a poor immune response to infection places individuals at increased risk for dementia.\u201d
Another risk<\/a> of COVID-19, and particularly severe forms of this disease, is thrombosis, a cause of strokes<\/a>. According to one large study, a stroke can double the risk<\/a> of developing dementia.
People with severe COVID-19 are more likely to have neurological symptoms of the illness, both during its acute phase and afterwards. And severe COVID-19 is more common<\/a><\/hl-trusted-source> in those who are older or have comorbidities, such as overweight or obesity, diabetes, chronic lung disease, and cancers.
Studies suggest that the best way to avoid neurological effects of COVID-19 is to optimize brain and body health in these ways:
Drug treatments to combat inflammation are also an option. Prof. Gelbard, who is now working on developing such a treatment, commented, \u201cWhat is sorely needed is an appropriate anti-neuroinflammatory intervention with a brain-penetrant therapy that can mitigate this type of neuroinflammatory response.\u201d
And, as several experts<\/a> have noted, vaccination against COVID-19 is one of the most effective ways of minimizing the risk of both severe COVID and long COVID, a view Dr. Snyder reiterated:
\u201cWhile we work to further understand the lasting impacts of COVID-19 on the brain, the take-home message for protecting your cognition is simple: Don\u2019t get COVID-19. The best way to not get COVID-19 is to get vaccinated.\u201d
As yet, it is unclear whether COVID-19 may be a risk factor for dementia.
Dr. Snyder told MNT<\/em> that \u201cThe ongoing COVID-19 pandemic gives us an unwelcome opportunity to study the impact of viral infection on the brain in the short and long term.\u201d
She added: \u201cPotential viral contributions to Alzheimer\u2019s and dementia have been long debated within the research community. However, no research to date has shown definitively that a virus can cause Alzheimer\u2019s disease. Because COVID-19 is still relatively new, we won\u2019t know if infection will have an impact on dementia risk for some time.\u201d
Prof. Gelbard concurred: \u201cUnfortunately, we believe this is the tip of the iceberg. Not to sound like an alarmist, but we echo the sentiments of public health experts: We may feel like we are done with COVID-19, but the virus is not done with us. We expect the aftershocks of this pandemic to continue amplifying the challenge of dealing with neurodegenerative disease in the elderly and immunocompromised.\u201d
\u201cIf you have had COVID-19, it doesn\u2019t mean you\u2019re going to get dementia. We\u2019re still trying to understand this relationship.\u201d
\u2013 Dr. Heather Snyder
While researchers have yet to arrive at conclusive evidence, it appears that the neurological and psychiatric effects of COVID-19 are likely to be with us for many years to come.
For live updates on the latest developments regarding COVID-19, click here<\/a>.<\/em><\/strong>
What do we know about the long-term neurocognitive impact of COVID-19, and what are we yet to learn? This Special Feature and podcast investigate<\/a>
Dr. Kelly Ann Fearnley lives with long COVID and persistent neurological and neurocognitive symptoms. In this article, she talks about her experiences.<\/a>
How might SARS-CoV-2 affect the brain? While many unknowns remain, we round up the evidence that has emerged so far. <\/a>
An increasing number of people known as 'long haulers' are saying they have 'long COVID,' experiencing long-term symptoms of COVID-19. MNT finds out\u2026<\/a>
What is long COVID? Read on to learn about what it is and how long recovery takes. This article also covers the symptoms, causes, and diagnosis of\u2026<\/a>
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For most, COVID-19 causes a few days of mild to moderate symptoms, but others feel the effects for months. Some of these effects are neurological, leading scientists to ask whether COVID-19 could increase the risk of dementia. Medical News Today looked at the evidence and spoke with experts to find out the latest views.Since the […]<\/p>\n","protected":false},"author":869,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"https:\/\/linksus2.linksus.net\/index.php\/wp-json\/wp\/v2\/posts\/1052"}],"collection":[{"href":"https:\/\/linksus2.linksus.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/linksus2.linksus.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/linksus2.linksus.net\/index.php\/wp-json\/wp\/v2\/users\/869"}],"replies":[{"embeddable":true,"href":"https:\/\/linksus2.linksus.net\/index.php\/wp-json\/wp\/v2\/comments?post=1052"}],"version-history":[{"count":0,"href":"https:\/\/linksus2.linksus.net\/index.php\/wp-json\/wp\/v2\/posts\/1052\/revisions"}],"wp:attachment":[{"href":"https:\/\/linksus2.linksus.net\/index.php\/wp-json\/wp\/v2\/media?parent=1052"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/linksus2.linksus.net\/index.php\/wp-json\/wp\/v2\/categories?post=1052"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/linksus2.linksus.net\/index.php\/wp-json\/wp\/v2\/tags?post=1052"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}