Study shows colds, flu can create short-lived, increased stroke risk in vulnerable children

A new study suggests that colds and other minor infections may temporarily increase stroke risk in children. The study found that the risk of stroke was increased only within a three-day period between a child's visit to the doctor for signs of infection and having the stroke.

The study was led by researchers at UCSF Benioff Children's Hospital San Francisco in collaboration with the Kaiser Permanente Division of Research.

''These findings suggest that infection has a powerful but short-lived effect on stroke risk,'' said senior author Heather Fullerton, MD, a pediatric vascular neurologist and medical director of the Pediatric Brain Center at University of California, San Francisco's (UCSF) Benioff Children's Hospital San Francisco.

''We've seen this increase in stroke risk from infection in adults, but until now, an association has not been studied in children.''

Strokes are extremely rare in children, affecting just five out of 100,000 kids per year. ''The infections are acting as a trigger in children who are likely predisposed to stroke," said Fullerton. ''Infection prevention is key for kids who are at risk for stroke, and we should make sure those kids are getting vaccinated against whatever infections – such as flu - that they can.''

The study appears in the online issue of Neurology.

In the study, researchers reviewed a Kaiser Permanente database of 2.5 million children and identified 102 children who had an ischemic stroke – a stroke that occurs as a result of an obstruction within a blood vessel supplying blood to the brain - without a major infection such as meningitis or sepsis.

The researchers then compared them with 306 children without stroke. Medical records for the group of children who had a stroke were reviewed for minor infections up to two years before their strokes.

The study found that the risk of stroke was increased only within a three-day time frame, which the researchers say represents a period of acute inflammation. As an infection resolves, the inflammation decreases, as does the stroke risk.

A total of 10 of the 102 children who had a stroke had a doctor visit them for an infection within three days of the stroke, or 9.8 per cent, while only two of the 306 control participants, or 0.7 per cent, had an infection during the same time period.

The children who had strokes were 12 times more likely to have had an infection within the previous three days than the children without strokes. The total number of infections over a two-year period was not associated with increased stroke risk. About 80 per cent of the minor infections identified by the researchers were upper respiratory.

''It's important the public does the things we can to prevent infection, like vaccinations, good hand washing and covering your mouth when you sneeze in order to protect all children, but it's especially important to help prevent stroke in someone who is otherwise predisposed,'' said Fullerton.

The study was supported by the National Institute of Neurological Disorders and Stroke.

Co-authors are Nancy Hills, PhD, associate professor in the UCSF Department of Neurology, and Stephen Sidney, MD, MPH, director of research clinics at Kaiser Permanente Northern California Division of Research.

UCSF Benioff Children's Hospital San Francisco creates an environment where children and their families find compassionate care at the forefront of scientific discovery, with more than 150 experts in 50 medical specialties serving patients throughout Northern California and beyond. The hospital admits about 5,000 children each year, including 2,000 babies born in the hospital.

UC San Francisco (UCSF), now celebrating the 150th anniversary of its founding, is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes top-ranked graduate schools of dentistry, medicine, nursing and pharmacy, a graduate division with nationally renowned programs in basic, biomedical, translational and population sciences, as well as a preeminent biomedical research enterprise and two top-ranked hospitals, UCSF Medical Center and UCSF Benioff Children's Hospital San Francisco.