Persistent loss of smell due to COVID-19 may better predict long-term cognitive and functional impairment

New insights into factors that may predict, augment, or protect against the impact of COVID-19 and the pandemic on memory and thinking skills have emerged from several studies presented today at the conference. International Alzheimer’s Association® (AAIC)®) 2022 in San Diego and virtually.

Among the key findings reported at AAIC 2022:

  • A group from Argentina found that persistent loss of smell may be a better predictor of long-term cognitive and functional impairment than the severity of initial COVID-19 illness.
  • According to a study from the Rush Alzheimer’s Disease Center in Chicago, hospitalization in an intensive care unit was associated with a twice as high risk of dementia in older people.
  • During the pandemic, female gender, not working, and lower socioeconomic status were associated with more cognitive symptoms in a large study population from nine Latin American countries.
  • In this same Latin American population, experiencing a positive lifestyle change during the pandemic (such as more quality time with friends and family or spending more time in nature) reduced the negative impact of pandemic on memory and thinking skills.

“COVID-19 has sickened and killed millions around the world, and for some, emerging research suggests there are long-term impacts on memory and thinking as well,” said Heather M. Snyder. , Ph.D., Vice President. Medical and Scientific Relations of the Alzheimer’s Association. “As this virus will likely be with us for a long time, identifying risk and protective factors for cognitive symptoms may aid in the treatment and prevention of ‘long COVID’ in the future.”

Persistent loss of smell predicts cognitive impairment better than COVID-19 severity
Argentinian researchers working with the Alzheimer’s Association Consortium on Chronic Neuropsychiatric Sequelae of SARS-CoV-2 Infection followed 766 adults aged 55-95 exposed to COVID-19 for one year and performed a series of regular physical, cognitive and neuropsychiatric tests. Of the study group, 88.4% were infected and 11.6% were controls.

Clinical evaluation showed functional memory impairment in two-thirds of infected participants, which was severe in half of them. Another group of cognitive tests identified three groups with reduced performance:

  • 11.7% showed memory impairment only.
  • 8.3% had impairment in attention and executive functions.
  • 11.6% had multidomain impairment (including memory, learning, attention and executive functions).

Statistical analysis revealed that persistent loss of smell was a significant predictor of cognitive impairment, but not the severity of the initial COVID-19 illness.

The more knowledge we have about the causes or at least predict who will experience the significant long-term cognitive impact of COVID-19 infection, the better we can track it and begin to develop methods to prevent it.

Gabriela Gonzalez-Aleman, LCP, Ph.D., Professor, Pontifical Catholic University of Argentina, Buenos Aires

A stay in the intensive care unit may signal a higher risk of dementia

Researchers from the Rush Alzheimer’s Disease Center (RADC), part of Chicago’s Rush University System for Health, used data from five diverse studies of older adults without known dementia (n=3,822) to look at ward hospitalizations intensive care unit (ICU). ICU hospitalizations have previously been linked to cognitive impairment in older patients, but few studies have examined whether they increase the risk of dementia.

They looked at Medicare claims records from 1991 to 2018 (before the pandemic) and checked each year for the development of Alzheimer’s disease and all types of dementia using a standardized cognitive assessment. During a mean follow-up of 7.8 years, 1991 (52%) participants experienced at least one ICU hospitalization; 1031 (27%) had an ICU stay prior to study entry; and 961 (25%) had a stay in intensive care during the study period.

The researchers found that, in analyzes adjusted for age, sex, education and race, intensive care hospitalization was associated with a 63% higher risk of Alzheimer’s dementia and at a 71% higher risk of all types of dementia. In models further adjusted to account for other health factors such as risk factors and vascular disease, other chronic medical conditions, and functional disabilities, the association was even stronger: ICU hospitalization was associated with a 110% higher risk of Alzheimer’s disease and a 120% higher risk of all types. dementia.

“We found that intensive care hospitalization was associated with a two-fold risk of dementia in community-dwelling older adults,” said Bryan D. James, Ph.D., an epidemiologist at RADC. “These findings could be important given the high rate of ICU hospitalizations among older adults, and particularly given the huge increase in ICU hospitalizations during the COVID-19 pandemic. Understanding the link between the ICU hospitalization and the development of dementia is more critical than ever.”

“Further research is needed to replicate these findings and elucidate factors that may increase the risk of dementia. For example, is it the serious illness that sends someone to the hospital or potentially modifiable procedures during hospitalization that lead to dementia risk? James added.

A positive lifestyle change during the pandemic can cushion cognitive symptoms
Investigators from Central and South American countries and the United States examined whether sociodemographic factors and life changes associated with the pandemic were linked to cognitive symptoms, including problems with memory, attention and other thinking skills, during the early stages of the pandemic.

In the study reported to AAIC, 2,382 Spanish-speaking adults between the ages of 55 and 95 (mean 65.3, 62.3% female) from nine Latin American countries responded to an online survey or over the phone, underwent electronic cognitive testing and completed an inventory assessing the positive and negative impacts of the pandemic between May and December 2020. Of the total study population, 145 (6.09%) experienced symptoms of COVID-19.

Participants came from: Uruguay (1,423, 59.7%), Mexico (311, 13.1%), Peru (153, 6.4%), Chile (152, 6.4%), Dominican Republic (117 , 4.9%), Argentina (106, 4.5%), Colombia (50, 2.1%), Ecuador (39, 1.6%), Puerto Rico (19, 0.8%) and Others ( 12.0.5%)

Main conclusions:

  • Female gender, not currently working, and lower socioeconomic status were all independently associated with more cognitive symptoms early in the pandemic.
  • Negative life changes during the pandemic, such as economic hardship and limited social activities, were significantly associated with more cognitive symptoms. However, this association was weaker among study participants who reported at least one positive life change during the pandemic, including spending more time with friends and family or more time outdoors in the nature.

“Identifying risk and protective factors for cognitive symptoms during the pandemic is an important step toward expanding prevention efforts,” said María Marquine, Ph.D., associate professor in the departments of Medicine and Psychiatry and Director of Disparities Research in the Division of Geriatrics, Gerontology, and Palliative Care at the University of California, San Diego. “Experiencing positive life changes during the pandemic might buffer the detrimental impact of negative life changes on cognitive symptoms.”

“This study is an example of how researchers from various countries in Latin America and the United States, many of whom had never worked together before and had limited resources, came together under difficult circumstances but with a common goal of advancing the scientific understanding of Alzheimer’s disease, and the important contributions that such multicultural partnerships can make,” added Marquine.

Leave a Comment