A simple infection in the body can have such a profound effect on the brain that a person’s IQ can drop, new research claims.
Danish researchers say the link is very real - and the more infections a person suffers, the bigger the damage to their brain power, Science reported.
This damage can last for ‘many years’, they warn.
While the effect was seen after infections in any part of the body - for example, the stomach, urinary tract or skin - the most ‘damage’ was seen following infections in the brain.
The researchers found that people who were hospitalized due to infection had an IQ score of 1.76 lower than the average.
And those with five or more hospital contacts with infections had an IQ score of 9.44 lower than the average.
The average IQ is said to be no higher than 115.
Correlation Clear
Researchers say the study is the largest of its kind to date, and it shows ‘a clear correlation’ between infection levels and impaired mental abilities. The study was published in the journal PLOS ONE.
Explaining why this effect may occur, study author Dr Michael Eriksen Benros, of the University of Copenhagen, said: “Infections can affect the brain directly, but also through peripheral [surrounding] inflammation, which affects the brain and our mental capacity.”
Infections have previously been associated with both depression and schizophrenia, and also proved 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. It may be the immune system that causes the mental impairment, not just the infection.
Normally, the brain is protected from the immune system, but with infections and inflammation, the brain may be affected.
Dr Eriksen Benros added: “We can see that the brain is affected by all types of infections. Therefore, it is important that more research is conducted into the mechanisms which lie behind the connection between a person’s immune system and mental health.’
The research was conducted in collaboration with researchers from the University of Copenhagen and Aarhus University.
It tracked 190,000 Danes born between 1974 and 1994, who had their IQ assessed between 2006 and 2012.
