24 May 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.
Medical Research: What should clinicians and patients take away from your report?
Response: Inflammation may be a common mechanism that influences both our physical and mental health. Infections can affect the brain directly, but also through peripheral inflammation, which affects the brain and our mental capacity. Infections have previously been associated with both depression and schizophrenia, and it has also been proven to affect the cognitive ability of patients suffering from dementia. This is the first major study to suggest that infections can also affect the brain and the cognitive ability in healthy individuals. Doctors should pay attention to individuals that are cognitive and mentally affected after hospitalization for a severe infection, where follow-up with neuropsychologists for instance would be indicated.
Medical Research: What recommendations do you have for future research as a result of this study?
Response: Research should focus on the specific molecular mechanisms responsible for the association between infections and immune-responses with cognition and mental health, in order to focus on prevention and potentially improved treatment of individuals with an immune-related etiology to their cognitive and mental problems.
Citation:
The Association between Infections and General Cognitive Ability in Young Men – A Nationwide Study
Published: May 13, 2015 DOI: 10.1371/journal.pone.0124005
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MedicalResearch.com Interview with: Dr. Michael Eriksen Benrós (2015). Number Of Infections Can Impact Cognitive Ability MedicalResearch.com
Last Updated on May 26, 2015 by Marie Benz MD FAAD