than people in the general population with no such infection, according to new data published on the preprint server medRxiv.
Researchers, led by Peter A. Hall, PhD, with the University of Waterloo (Ont.), found that COVID infection is associated with executive dysfunction among young and middle-aged adults, including for those not exposed to intubation or hospitalization.
The findings have not been peer reviewed.
The study included a representative cohort of 1,958 community-dwelling young and middle-aged adults. It used a balanced proportion of infected and uninfected people to estimate the link between SARS-CoV-2 infection and cognitive/executive dysfunction.
The authors noted that the survey was conducted from Sept. 28 to Oct. 21, 2021, when the primary variant in Canada was Delta.
The research was a cross-sectional observational study with data from the ongoing Canadian COVID-19 Experiences Survey. It included equal representation of vaccinated and vaccine-hesitant adults aged 18-54 years. COVID-19 symptoms ranged from negligible to life-threatening cases requiring hospitalization.
Half in the cohort (50.2%) received two vaccine shots; 43.3% had received no shots; and 5.5% received one shot, but were not intending to receive a second shot.
Dose-response relationship
According to the paper, those with prior COVID-19 infection, regardless of symptom severity, reported a significantly higher number of symptoms of executive dysfunction than their noninfected counterparts (mechanical adjustment, 1.63, standard error, 0.08; 95% confidence interval, 1.47-1.80; P = .001).
The researchers also found a dose-response relationship between COVID-19 symptom severity and cognitive dysfunction. Those with moderate and very/extremely severe COVID-19 symptoms were linked with significantly greater dysfunction.
“This reinforces what we’re hearing about – that COVID is not ‘one and done.’ It can have lasting and quite subtle and damaging effects on the human body,” William Schaffner, MD, infectious disease specialist with Vanderbilt University, Nashville, Tenn., said in an interview.
Measuring executive functioning – including the ability to make sound decisions – is something other studies haven’t typically addressed, he said.
Men were likely to report more cognitive dysfunction symptoms than women (beta, 0.15; P < .001). Younger adults (25-39 years) were more likely to experience cognitive dysfunction than those age 40-54 (beta, 0.30; P < .001).
Dr. Schaffner said it was troubling that young people are more likely to experience the dysfunction.
“When we think of ‘brain fog’ we think of older persons who are already predisposed to have more memory lapses as they get older,” he said.
The link between cognitive dysfunction and COVID-19 infection has been shown in other studies, but many have not used representative samples and have not compared results with noninfected controls in the general population, the authors wrote.
Executive dysfunction was measured using four questions from the Deficits in Executive Functioning Scale. Respondents were asked how often they have experienced these scenarios in the past 6 months:
- “I am unable to inhibit my reactions or responses to events or to other people.”
- “I make impulsive comments to others.”
- “I am likely to do things without considering the consequences for doing them.”
- “I act without thinking.”
“This makes it even more important that we talk about vaccination,” Dr. Schaffner said, “because clearly the more seriously ill you are, the more likely this sort of thing is likely to happen and vaccines have been shown time and again to avert hospitalizations and more serious illness. It also makes more important the monoclonal antibody treatments we have and the antivirals, which will prevent the evolution of mild disease into something more serious.”
This research was supported by a grant from the Canadian Institutes for Health Research, Institute for Population and Public Health. The study authors and Dr. Schaffner disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.