Predictors different among sexes, races.

A protein in the blood that is considered to be a key indicator of future heart disease may vary considerably among women and men, as well as blacks and whites, concludes research at the University of Texas Southwestern Medical Center, Dallas.

C-reactive protein, or CRP, is released as part of the human body's inflammation response. Infections and inflammation brought on by various illnesses can be the reason CRP levels in the blood rise. Abnormal fatty deposits on the interior walls of arteries that are prone to rupture and induce heart attacks also may be the reason for elevated levels of CRP, which is why the protein recently has been touted as a means to determine the relative risk of heart disease in some patients.

Current recommendations for CRP testing use the same cut points to determine risk for everyone. However, one size may not fit all, and there might be important variations between sexes and races. "Our goal was to determine the distribution of CRP levels among different genders and races," explains Amit Khera, assistant professor of internal medicine and lead author of the study.

"CRP as a risk factor for cardiovascular disease has been studied mainly in white men and in research groups that do not necessarily represent the community at large. The recommended thresholds of CRP may not appropriately reflect CRP distributions for black men and women."

Researchers measured CRP levels in men and women ages 30 to 65. They found that patients with a higher body mass index (a measurement of obesity) had correspondingly elevated levels of CRP. Moreover, women typically had much greater levels in their blood than men, and blacks had higher levels than white patients. CRP levels in white women were more elevated than those in black men. Yet, black men have disproportionately higher rates of cardiovascular disease than white women.

"Our study was a snapshot of a population, but it showed that white women have higher levels of CRP than both black and white men. Since white women have lower rates of cardiovascular disease, this study raises some questions about how best to use CRP in the real-world setting," notes Khera. "We need more research to determine if these differences translate into differences in cardiovascular events."