Boys, Black Children Have Higher Risk of Stroke
St. Paul, MN – Boys are 28 percent more likely than girls to
have a stroke, and black children are more than twice as likely
to have a stroke as other ethnic groups, according to a study
in the July 22 issue of Neurology, the scientific journal of
the American Academy of Neurology.
Researchers identified 2,278 first admissions for childhood stroke
in a 10-year period in California by examining a statewide hospital
discharge database. Children were one month through 19 years
of age and were classified by their parent or guardian as white,
black, Hispanic, Asian or other. Boys made up 51 percent of the
population, and girls made up 49 percent.
Ischemic stroke (the most common type of stroke, resulting from
blocked arteries) accounted for 51 percent of the cases. Hemorrhagic
stroke accounted for the rest, and was broken down into intracerebral
hemorrhage (vessels bleed into the brain) and subarachnoid hemorrhage
(abnormal vessels rupture near the membrane surrounding the brain).
The annual stroke incidence rate was found to be 2.3 strokes
per 100,000 children.
"Adult stroke risk is well documented, but little is known about
childhood stroke," said study author Heather J. Fullerton, MD,
a pediatric stroke neurologist at the University of California,
San Francisco. "A lot remains to be understood."
Boys were found to be 28 percent more likely than girls to have
a stroke of any type. More than 4 percent of all stroke cases
also had head trauma, which is a risk factor for childhood stroke.
Boys were almost twice as likely to have a diagnosis of trauma.
Yet after excluding cases with trauma, boys still had an increased
risk for ischemic stroke. This suggests that other factors contributed
to the higher risk in boys, Fullerton noted.
Black children had more than twice the risk of stroke overall.
Asian children had similar risks as white children for all stroke
types. Hispanic children had the lowest risk for ischemic stroke
and intracerebral hemorrhage.
Nearly 7 percent of the ischemic stroke cases also had sickle
cell disease (a blood disorder affecting the red blood cells),
which is another known risk factor for childhood stroke. In black
children who had an ischemic stroke, more than 38 percent also
had sickle cell disease. After excluding cases with sickle cell
disease, however, black children still had a 61 percent increased
risk of stroke. This suggests that sickle cell disease does not
completely explain why black children are having more strokes,
Previous studies have shown that adult males have higher rates
of ischemic stroke and intracerebral hemorrhage. Likewise, black
adults have been shown to have a higher risk of stroke. These
findings have been explained by the higher rates of stroke risk
factors (smoking, diabetes and hypertension) in these groups.
"These explanations cannot be used to account for our findings
because risk factors like hypertension and smoking do not play
a significant role in childhood stroke," Fullerton said. "Additional
population-based studies are needed to explore unrecognized risk
factors like genetic predisposition or unidentified environmental
risks, and shed light on why children have strokes."
The study also found that infants one month to one year old had
the highest rates of any age group for ischemic stroke and intracerebral
hemorrhage. Teens 15 through 19 years old were found to have
the highest rates of subarachnoid hemorrhage.
The American Academy of Neurology, an association of more than
18,000 neurologists and neuroscience professionals, is dedicated
to improving patient care through education and research. A neurologist
is a doctor with specialized training in diagnosing, treating
and managing disorders of the brain and nervous system such as
stroke, Alzheimer's disease, epilepsy, Parkinson's disease, autism
and multiple sclerosis.
For more information about the American Academy of Neurology,
visit its web site at www.aan.com.