CHAPEL HILL - After eliminating the influence of smoking, high blood pressure, diabetes, education levels and existing heart disease, black Americans still face a 38 percent higher risk of stroke than U.S. whites do, a large new study indicates. No one knows why.
Before accounting for those factors, black men face a two-and-a-half times greater chance of stroke than white men do. Black women's stroke rate falls about half way between black men and white men, and the rate for white women is lowest of the four groups studied.
"We already have good data on the fact that blacks and whites differ in stroke mortality, with blacks being more likely to die from stroke," said Dr. Wayne D. Rosamond, assistant professor of epidemiology at the University of North Carolina at Chapel Hill School of Public Health. "What this study gives us is new data on the incidence of the disease, which is a direct measure of their risk of getting it.
"Differences between whites and blacks may result from obesity or diet or factors we haven't identified yet."
A report on the research appears in the just-published April issue of the journal Stroke. Besides Rosamond, UNC-CH authors are Drs. Lloyd E. Chambless, research professor of biostatistics, and Chin-Hua Wang, research investigator in biostatistics.
The study, known as Atherosclerosis Risk in Communities, or ARIC, involved following a group of 15,792 men and women ages 45 to 64 an average of 7.2 years from 1987 to 1995.
Researchers recruited subjects from four geographically diverse U.S. communities - Washington County, Md.; Jackson, Miss.; Minneapolis, Minn.; and Forsyth County, N.C. They determined stroke rates from yearly telephone contacts with participants and careful searches of area hospital records.
During the period analyzed, they found 267 strokes, 83 percent of which
were classified as ischemic stroke and 17 percent internal blee
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Contact: David Williamson
David_Williamson@unc.edu
919-962-8596
University of North Carolina at Chapel Hill
13-Apr-1999