THURSDAY, April 7 (HealthDay News) -- Gaps in care for black and white U.S. veterans have been reduced over the past decade as the VA Health Care System improved access to screenings and treatment of high-risk conditions among all patients. But major disparities persist in control of cholesterol, diabetes and high blood pressure, a new study says.

Researchers assessed 10 clinical performance measures among a national sample of more than 1.2 million VA enrollees between 2000 and 2009.

"The VA has narrowed care gaps that are directly under the control of the providers -- ordering tests, referring to the appropriate specialist, and conducting screenings," study author Amal Trivedi, a research investigator at the Providence VA Medical Center and an assistant professor at Brown University's medical school, said in a news release.

But he and his colleagues found as much as a 9 percent difference between black and white veterans in measures indicating whether patients' blood pressure, cholesterol and diabetes were under control.

Not only do these three conditions affect how healthy people are and how long they live, they also have a major impact on health costs.

The reasons for the racial disparities aren't known and further research is needed, Trivedi said.

The study appears in the April issue of the journal Health Affairs.

More information

The U.S. Centers for Disease Control and Prevention has more about health disparities.