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MONDAY, July 21, 2003 (HealthDayNews) -- The first large-scale study of stroke in children finds boys are more likely to have them than girls, and black children have twice the risk of other ethnic groups.
It is a more common affliction than generally believed, says study author Dr. Heather J. Fullerton, a clinical instructor in neurology at the University of California in San Francisco. In fact, the study, which appears in the July 22 issue of Neurology, states that "stroke is an increasingly recognized cause of childhood disability."
Fullerton and her colleagues looked at all the California hospital admissions for stroke in patients aged 1 month through 19 years and found 2,278 cases, an incidence of 2.3 in 100,000. The incidence of ischemic stroke, caused by an artery blockage, and hemorrhagic stroke, caused by a burst artery, was almost identical.
The overall incidence was about as expected, Fullerton says. Previous studies have reported an incidence in the neighborhood of 2.5 per 100,000, "but they did not look at ethnic incidence, and they had a much smaller number of patients."
Differences quickly emerged when the researchers broke the incidence down by sex and ethnic group. To start with, the incidence was 28 percent higher for boys than for girls.
That is understandable to some degree, Fullerton says, because boys roughhouse more than girls. Evidence of trauma -- head damage -- was found in twice as many boy patients as girls.
"But it didn't seem that trauma fully accounted for the difference, so we think that something else must be involved," Fullerton says. It is known that adult men have a higher risk of stroke than women, which has been explained by a higher incidence of risk factors such as diabetes and high blood pressure, but it would be "sheer speculation" to extend that explanation to children, she says.
The most striking difference was by ethnic groups. Hispanic children had a lower incidence than whites, Asians were on a level with whites and black children had double that risk. The severity of strokes, as measured by the number of days spent in the hospital, was the same for all the groups.
Again, there is a partial explanation for the racial difference. Black children are much more likely to have sickle cell disease, which raises the risk of stroke. Yet when sickle cell disease was taken out of the equation, the risk for black children was still more than 60 percent higher. There is no obvious reason for that difference, Fullerton says.
The San Francisco group will seek explanations, she says. "The study we plan on doing will be a population-based study at childhood stroke that will look at a number of risk factors that may not have been identified," she says. "Finding an explanation will take a while."
An organization that offers information and assistance is the Pediatric Stroke Network. Learn more about stroke in children from the National Institute of Neurological Disorders and Stroke.