According to a new study, children who are affected by pertussis, or "whooping cough" in early childhood appear to have an increased risk of epilepsy later in childhood, Reuters reports.

Lead author Dr. Morten Olsen of the Aarhus University Hospital in Denmark said,

 "Although the association we identify may be important on a population level, the individual child admitted to hospital with pertussis will have a very low risk of epilepsy."

For the new study, researchers used a national database in Denmark. They studied all 47,000 patients born between 1978 and 2011 who had been diagnosed with pertussis. About half of these patients were diagnosed before six months of age.

The study revealed that when compared to a group of similar people matched by sex and year of birth, the individuals who had been diagnosed with pertussis had a higher risk of childhood epilepsy.

Around one percent of those in the comparison group were diagnosed with epilepsy by age 10, compared to 1.7 percent of those in the pertussis group.

The report was published in the journal JAMA.

"The finding certainly is novel," said Adam L. Hartman, MD, an associate professor of neurology and pediatrics at Johns Hopkins Children's Center, who was not a part of the study.

"Seizures in the short term have been associated with pertussis infection but this study shows that there also might be long-term effects," he said, though emphasizing that the study does not determine causation, mothering reports.

The study also revealed that children diagnosed with pertussis after age three were not at increased risk for epilepsy.

Dr. Eugene D. Shapiro of the Yale School of Public Health in New Haven said that it was possible that the low blood oxygen levels due to coughing fits may cause damage to the brain and increase the risk of epilepsy.

 "It seems plausible that epilepsy would occur in children who had pertussis early in life," and the infection may also increase the risk of other brain complications like mental retardation, said Dr. James D. Cherry, professor of pediatrics at the David Geffen School of Medicine at UCLA in Los Angeles who was not part of the new study.

"Presently we're recommending vaccinating all pregnant women, so the antibodies transmitted from the mother would prevent pertussis" in infancy, helping to cover the gap between birth and first vaccine dose at age two months, Cherry told Reuters Health by phone.