NEW ORLEANS -- Blacks in the South apparently get a double whammy of stroke risk: They die at much higher rates than either Southern whites or blacks who live elsewhere.
Researchers have long known that stroke deaths are greater among blacks and people in the "Stroke Belt" across the eastern part of the nation's midsection. But they thought the combined risk posed by race and geography was small.
"Much to our surprise, the finding is: No, it's not," said George Howard, a biostatistician who presented his research Wednesday at an American Stroke Association conference in New Orleans.
The rate of stroke deaths among black men in the South was 51 percent higher than it was among blacks in other parts of the country. And black men in the South had roughly four times the risk of dying of a stroke as white men living outside the South.
"That's a pretty big difference," Howard said.
Howard, chairman at the University of Alabama at Birmingham School of Public Health, compared stroke deaths in 10 Southern states to those in 11 non-Southern states with large enough black populations to make comparisons possible, including California, Texas and New York.
He used information from the National Center for Health Statistics from 1997 through 2001, and adjusted it to take into account how many blacks and whites live in each state.
Among white men ages 55 to 64 living in the South, the stroke death rate was 49 deaths per 100,000 people -- 29 percent higher than the rate among white men living elsewhere. Among black men in the South, the rate was 159 deaths per 100,000 people, compared with 105 for black men living elsewhere.
Trends were similar among women.
Leading theories for the racial and geographic differences are that Southerners are more likely to smoke, be overweight, have high blood pressure and be in poor general health. Lack of good medical care also may be involved.
"Some of those Stroke Belt states are some of the poorest in the country," said Dr. Joseph Broderick, chairman of neurology at the University of Cincinnati School of Medicine.
As for whether moving from the South would help, that is not clear at all.
"I was brought up in what's called the buckle of the Stroke Belt," and then moved to Alabama, Howard said. "Did I bring the risk with me or did I leave it in eastern North Carolina?"
The National Institute of Neurological Disorders and Stroke funded his study and another presented at the conference which found that whites were twice as likely as blacks to have "prehypertension," a new category the government set last year for mildly elevated blood pressure -- a reading of 120 to 139 over 80 to 89.
But blacks with prehypertension were far more likely to suffer strokes or heart disease as a consequence, the study of more than 80,000 around the country found.
"The population should be aware of this category and know that this is a new risk," said Daniel Lackland, an epidemiologist at Medical University of South Carolina in Charleston.
Blood pressure drugs are not recommended for prehypertension unless people have diabetes or other conditions. Instead, doctors urge people to watch their diets and salt intake.
Other studies at the conference hinted that genetic differences may play a role in higher stroke risks for blacks. Three separate teams found that stroke victims were more likely to have variations in a potential "stroke gene" recently identified in Iceland. One of the teams found that such variations were more common in blacks than in whites.
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