Data from a large managed care plan with 16 hospitals in Northern California show that black children have double the risk of stroke compared with white children.

Stroke risk among Hispanic children also initially appeared to be higher than in white children, but that excess risk was eliminated after controlling for a number of variables, Dr. Heather J. Fullerton of the University of California at San Francisco said here during a presentation of her team's findings at the American Stroke Association's International Stroke Conference 2007.

The study cohort, from the Kaiser Permanente Medical Care Program, consisted of 662,692 children, 54% white, 16% Hispanic, 13% Asian, 8% black and 9% other ethnicities seen at Kaiser Permanente between 1993 and 2004.

There were 223 strokes, of which 154 were ischemic and 69 were hemorrhagic. There was an overall incidence rate of 5.5 strokes per 100,000 person-years.

Stroke incidence among white children was 4.88 strokes per 100,000 person-years. The incidence among black children was 10.13 per 100,000 person-years, for a relative risk of 2.08 compared with whites. The incidence among Hispanics was 8.09 and among Asians it was 5.31 per 100,000 person-years, for a relative risk of 1.66 and 1.08, respectively.

The investigators calculated incidence rates of childhood versus neonatal strokes. For childhood stroke among whites, the incidence was 2.52, for blacks it was 6.08, for Hispanics it was 3.20 and for Asians it was 3.07 per 100,000 person-years.

The incidence of neonatal strokes was 32.2 for white infants, 58.7 for blacks, 35.4 for Hispanic infants and 21.3 per 100,000 person-years for Asian infants.

When analyzed according to relative risk, Dr. Fullerton reported that the relative risk was 2.32 for blacks, 1.22 for Hispanics, and 1.17 for Asian children compared with whites.

For neonatal strokes, the relative risk was elevated, and only slightly, for black infants. Neonatal stroke risk was statistically equal among the other races.

Dr. Fullerton told meeting attendees that her investigators controlled for sickle cell, infection and trauma, but the two-fold higher risk of stroke in black children remained. She told Reuters Health that the database is representative of all children in northern California, although it probably doesn't capture the extremes of the very wealthy and the very poor.

Dr. Fullerton said she and her colleagues are now using a case-control cohort to distinguish unidentified risk factors. While black adults have about twice the risk of stroke as white adults, this is largely attributed to modifiable risk factors. This explanation is less plausible in childhood, Dr. Fullerton said.



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