London, Jul 17 (IANS): Severe infections during childhood that lead to hospitalisations could lower academic performance in adolescence, a new study has found.

The study, published in The Pediatric Infectious Disease Journal, suggested that higher numbers of hospitalisations for infections were associated with a reduced probability of completing ninth grade, as well as with lower test scores.

"Our findings extend our understanding regarding the association between particularly severe infections during childhood and adolescence and cognitive achievement," said co-author Köhler-Fosberg from the Aarhus University Hospital in Denmark.

For the study, the researchers included nationwide data of 598,553 children born in Denmark between 1987 and 1997.

The researchers looked at hospital admission for infections, an indicator of moderate to severe infections and prescriptions for anti-infective drugs in primary care, reflecting less-severe infections.

These infection measures were analysed for their association with two measures of later school achievement -- completing ninth grade and average scores on the final ninth-grade school examinations.

The researchers found that any hospital contact for infections was associated with an 18 per cent reduction in the odds of completing ninth grade.

The more hospitalisations for infections, the lower the odds of reaching this educational milestone -- children with five or more infections requiring hospitalisation had a 38 per cent reduction in the odds of completing ninth grade.

Among children who completed ninth grade, hospitalisation for infections was associated with a small but significant reduction in final exam scores.

Primary care treatment with anti-infective drugs -- indicating the presence of common, less-severe infections -- was unrelated to the chances of completing ninth grade.

Aside from brain damage caused by serious infections like rubella or encephalitis, "there is growing awareness that a wider range of infections may have a more subtle and/or delayed impact on brain function," the researchers noted.