Researchers at McGill University have found that the gap in life expectancy between whites and blacks in America still exists but has narrowed substantially.

The McGill study, "Trends in the Black-White Life Expectancy Gap in the United States, 1983-2003," found that the gap declined to a historic low of 5.3 years in 2003 from 7.1 years in 1993.

U.S. blacks can now expect to live on average to 72.7 years, while whites can expect to live to 78 years.

"What we're seeing is partly a swing of the pendulum back to the trend of the '70s and early '80s," said lead author Sam Harper, a postdoctoral fellow in McGill's Department of Epidemiology, Biostatistics and Occupational Health.

That was before a steep increase in crack-related homicides and HIV/AIDS deaths among younger blacks caused the gap to widen.

The McGill researchers studied data complied by the U.S. National Vital Statistics System, which is maintained by the National Center for Health Statistics.

They found the decline in the life expectancy gap was larger among black males. The gap in that gender group declined by 25 per cent from the previous decade, from 8.44 to 6.33 years.

They noticed a decrease in mortality among black males 15-49 from homicide, HIV/AIDS and unintentional injuries (accidental death). A lack of improvement in death rates of older black men from heart disease kept the overall gap from narrowing even further.

The female gap decreased by one year between 1993 and 2003, from 5.59 years to 4.54. Half of that was attributed to improvements in mortality among blacks in heart disease, homicide and unintentional injuries.

The study concluded that a substantial life expectancy gap still exists but that it can be further reduced with concerted intervention from public health officials.

"The crucial thing here," said Harper, "is that the black-white gap is not fixed and it's not a mystery. It can change because of improvements in a small number of causes of death. This means the remaining gap can be addressed through greater public health efforts and improvements in health care."

Harper's research, conducted with Dr. John Lynch, Canada Research Chair in Population Health, is published in the March 21 issue of the Journal of the American Medical Association.