While black males still live five-and-a-half years less than their white counterparts on average, a study shows that in the past decade, the U.S. has made unprecedented progress in decreasing the life-expectancy gap between blacks and whites.

According to “Trends in the Black-White Life Expectancy Gap 2003-2008,” published June 6 in the Journal of the American Medical Association, the gap in life expectancy between blacks and whites shrank approximately one year between 2003 and 2008, putting the racial disparity at its lowest rate ever.

The lead author of the report, Sam Harper of McGill University in Montreal, says the study carries a “dual message.”

“The gap in life expectancy between blacks and whites is now as small as it's ever been, and I think that's an important sign of progress,” Harper says. “That being said, the gap is still substantial. There is still work to be done.”

Harper and his co-authors used mortality statics from the Centers for Disease Control and Prevention to estimate life expectancy at birth and compare differences between non-Hispanic white and black Americans.

Dr. Clyde Yancy, professor of medicine and chief of cardiology at Northwestern University's Feinberg School of Medicine, calls the study's findings “truly encouraging” and emphasizes the need for further progress.

“Rather than trumpet this as a success, it should continue to be a cause for concern, and some would argue it should be a call to arms,” he says.

In the story of the life-expectancy gap, heart disease stands as both the hero and the villain. The disease was the biggest contributor to the decline in the racial gap and to the size of the disparity to begin with—deaths from heart disease ranked as the No. 1 reason for the gap between white and black women in 2003 and 2008.

According to the American Heart Association's 2012 statistical update, between 1998 and 2008 the rate of deaths attributable to cardiovascular disease declined by 30.6%, but in 2008, blacks were still 30% more likely to die of heart disease than whites.

The AHA has had a “sharpened focus” on blacks for the past 15 years, says Pamela Garmon Johnson, AHA's vice president of health equities and multicultural initiatives.

While much of that focus has involved increasing awareness and encouraging healthy living, the AHA has turned its attention toward healthcare providers in minority communities. Johnson says the AHA is trying to “hold those clinics and hospitals accountable” for the well-being of their patients.