People who have had an infection that made them so sick they had to be hospitalized may have IQs that are slightly lower than average, a new study suggests.
Researchers from the University of Copenhagen and Aarhus University in Denmark examined the hospital records of 190,000 Danish men born between 1974 and 1994. All the men took IQ tests at age 19, as part of the process of signing up for Denmark’s mandatory draft. The tests were designed to assess their logical, verbal, numerical and spatial reasoning.
After adjusting for factors known to track with people’s IQ scores, such as social conditions and the education levels of their parents, the researchers found that the average IQ score of the men who had been hospitalized for an infection before they took the IQ test — about 35 percent of the study cohort — were 1.76 points below the average of the men in the study who had not been hospitalized for an infection.
“Infections in the brain affected the cognitive ability the most, but many other types of infections severe enough to require hospitalization can also impair a patient’s cognitive ability,” study author Dr. Michael Eriksen Benrós, a researcher at the National Centre for Register-Based Research, said in a statement.