Infections of the stomach, urinary tract or skin may affect a person's cognitive abilities and IQ, according to a recent Danish study.
In a study the largest of its kind to date, researchers from two Denmark institutions — the University of Copenhagen and Aarhus University — tracked 190,000 Danes born between 1974 and 1994 who had had their IQ assessed between 2006 and 2012.
Highlighted below are six findings from the study.
1. Of the 190,000 Danes who participated in the study, 35 percent had been hospitalized with infections before the IQ testing was conducted.
2. The research demonstrated a correlation between hospitalization due to infection and impaired cognition corresponding to an IQ score of 1.76 lower than the average.
3. People with five or more hospital contacts with infections had an IQ score of 9.44 lower than the average.
4. The study revealed a clear relationship between the number of infections and the effect on cognitive ability, which stengthened based on the frequency and severity of the infections.
5. While infections in the brain affected cognitive ability most significantly, many other types of infections severe enough to require hospitalization also impaired patients' cognitive ability.
6. The immune system of the hospitalized patients itself affected the brain so significantly that the person's IQ and cognitive ability was impaired many years after the infection had been cured.
"Infections can affect the brain directly, but also through peripheral inflammation, which affects the brain and our mental capacity," said senior researcher Michael Eriksen Benrós, MD, PhD. "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."
According to Dr. Eriksen Benrós, it is important to conduct additional research into the connection between a person's immune system and mental health.
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