DALLAS (AP) - Researchers say they may have found a new clue as to why blacks are at greater risk of dying from heart disease than whites.
In the largest study of its kind, blacks with high blood pressure were found to have thicker hearts than whites with high blood pressure. It's a condition called left ventricular hypertrophy, or enlarged heart.
"This is a marker for increased damage to the heart and may explain why there is a more adverse outcome of cardiovascular mortality, heart attacks, stroke and heart failure among blacks," said lead researcher Dr. Jorge Kizer, an assistant professor of medicine and public health at Weill Medical College of Cornell University in New York.
Blacks suffer from hypertension more than other racial groups. In 2000, heart disease deaths were 29 percent higher among blacks and stroke death rates were 40 percent higher than other groups, according to the Centers for Disease Control and Prevention.
In the study, researchers assessed 1,060 blacks and 580 whites by measuring their blood pressure, heart wall thickness and vascular tone. The findings revealed that blacks had a higher average of left ventricular mass index and wall thickness that persisted even after researchers adjusted for age, gender, and clinical risk factors such as blood pressure treatment and artery stiffness.
When researchers adjusted for additional factors such as socio-economic level, education, smoking and cholesterol, they found that ventricular hypertrophy was nearly double that of whites and the increase in heart-wall thickness among blacks was 21/2 times that of whites.
"It has been well-documented that blacks have higher cardiovascular mortality rates, but the basis of that is not clear," said Dr. Mark H. Drazner, an associate professor of medicine at the University of Texas Southwestern Medical Center. "This study could be a clue that explains the difference in mortality."
Drazner said the findings indicate that the effect of hypertension on blacks is likely the contributing to the mortality rate.
"The effects of hypertension need to be targeted if you're going to reduce cardiovascular mortality gap between the two ethnic groups," he said.
Kizer said that while more studies are needed to confirm the findings, the study could lead to the development of more drugs that can slow left ventricular hypertrophy.
Some studies already suggest that some high blood pressure medications, such as angiotensin receptor blockers or ARBs, help reduce heart thickening. A recent study, however, showed that the drugs worked better for whites than blacks.
Kizer said that could have been a statistical glitch, but it indicates that more work is needed to sort out strategies in how to treat hypertension in blacks.
