The latest findings from the historic Dallas Heart Study have ruled out one of the most prominent explanations of why elevated levels of a fat-carrying protein called "lipoprotein(a)" lead to increased risks for heart attacks among whites but not among African-Americans.
Researchers say the study, which appeared last month in the journal Circulation, points to the need for further research to determine whether African-Americans have a genetic mechanism that protects them from the risks of lipoprotein(a), also known as Lp(a). If such a mechanism is found, doctors might be able to use the information to develop therapies and drugs that reduce heart-attack risks for everyone.
In the study, statisticians from Rice University in Houston and medical researchers from The University of Texas Southwestern Medical Center at Dallas conducted a statistical analysis that looked for a relationship between increased levels of Lp(a) and increases in coronary calcium, a leading indicator of coronary atherosclerosis.
"We know from prior research that elevated plasma levels of Lp(a) are an independent risk factor for cardiovascular disease among whites, and we also know that African-Americans have twofold to threefold higher plasma levels of Lp(a) than whites, but they do not have a correspondingly higher rate of heart attacks," said Rudy Guerra, professor of statistics at Rice and the lead author of the paper. "Our study found no independent relationship between plasma levels of Lp(a) and coronary calcium in either whites or African-Americans, which indicates that some other mechanism is at work."