Author Interviews, Cognitive Issues, Infections, PLoS / 24.05.2015
Number Of Infections Can Impact Cognitive Ability
MedicalResearch.com Interview with:
Dr. Michael Eriksen Benrós
Mental Health Centre Copenhagen
University of Copenhagen Faculty of Health Sciences
Copenhagen NV, Denmark,
National Centre for Register-based Research
Aarhus University Denmark
Medical Research: What is the background for this study?
Response: It is increasingly recognized that infections and immune responses can affect the brain and activate immunocompetent cells within the brain, influencing on neuronal signal transduction and possibly cognition. Impaired cognition has been observed in association with several infections and with elevated levels of CRP in smaller studies. Furthermore, experimental activation of inflammatory reactions in healthy volunteers has been shown to induce short-term reduced cognitive performance. Moreover, particularly patients with infection in the brain or sepsis have been shown to have affected cognition in long time periods after the infection has been cleared, thus infections might also have a longer lasting effect on cognition. However, large-scale longitudinal studies had been lacking on the association between infections and cognitive ability in the general population.
Medical Research: What are the main findings?
Response: Our study is the first large-scale study utilizing the extensive Danish registers to follow 190,000 males that had their IQ assessed at conscription, out of which 35% had a previous hospital contact with infection before the IQ testing was conducted. Our research shows a correlation between severe infections with a hospital contact and subsequent impaired cognition corresponding to an IQ score of 1.76 lower than the average. People with five or more hospital contacts with infections had an IQ score of 9.44 lower than the average. The study thus shows a clear dose-response relationship between the number of infections. Furthermore the effect on cognitive ability increased with the temporal proximity of the last infection and with the severity of the infection. Infections in the brain affected the cognitive ability the most, but many other types of infections severe enough to require a hospital contact where also associated with impairment of the cognitive ability.
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