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

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

Among the key findings reported at AAIC 2022:

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

“COVID-19 has sickened and killed millions of people 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. of 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 help with treatment and prevention of ‘long COVID’ in the future.”

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

Clinical evaluation showed impaired working memory in two-thirds of the infected participants, which was severe in half of them. Another set of cognitive tests identified three groups with impaired performance:

  • 11.7% showed memory impairment only.
  • 8.3% presented impaired attention and executive function.
  • 11.6% showed multidomain impairment (including memory, learning, attention, and executive function).

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

The more information we have about what causes or at least predicts who will experience significant long-term cognitive impact from COVID-19 infection, the better we can track it down and start developing 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 indicate an increased risk of dementia

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

They reviewed Medicare claims records from 1991 to 2018 (before the pandemic) and annually checked for the development of Alzheimer’s disease and all types of dementia using a standardized cognitive assessment. During a median follow-up of 7.8 years, 1,991 (52%) participants experienced at least one ICU hospitalization; 1,031 (27%) had an ICU stay prior to study enrollment; and 961 (25%) had an ICU stay during the study period.

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

“We found that ICU hospitalization was associated with twice the risk of dementia in older adults in the community,” said Bryan D. James, Ph.D., an epidemiologist at the RADC. “These findings could be significant given the high rate of ICU hospitalization in older people, and especially given the tremendous increase in ICU hospitalizations during the COVID-19 pandemic. Understanding the link between ICU hospitalization and the development of dementia is of paramount importance now more than ever.”

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

A positive lifestyle change during the pandemic can buffer cognitive symptoms
Researchers from countries in Central and South America and the United States examined whether sociodemographic factors and life changes associated with the pandemic were related to experiencing cognitive symptoms, including problems with memory, attention, and other thinking skills. , during the early phases of the pandemic.

In the study presented at the AAIC, 2,382 Spanish-speaking adults ages 55 to 95 (average 65.3 years, 62.3% women) from nine Latin American countries completed a survey online or by phone, underwent electronic cognitive tests and completed an inventory to assess 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 were 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%)

Key results:

  • Female gender, not currently working, and lower socioeconomic status were independently associated with more cognitive symptoms during the early part of 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 spending more time outdoors in nature.

“Identifying risk and protective factors for cognitive symptoms during the pandemic is an important step toward developing prevention efforts,” said Maria 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. “The experience of positive life changes during the pandemic could buffer the detrimental impact of negative life changes on cognitive symptoms.”

“This study is an example of how researchers from diverse 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 the common goal of advancing scientific knowledge. about Alzheimer’s, and the important contributions that such multicultural partnerships can make,” added Marquine.

Leave a Comment