The gap in life expectancy between black and white Americans is at its narrowest since the federal government started systematically tracking it in the 1930s, but a difference of nearly four years remains and federal researchers have detailed why in a new report.

They found that higher rates of death from heart disease, cancer, homicide, diabetes and infant mortality accounted for more than half the black disadvantage in 2010, according to the report by the National Center for Health Statistics, the federal agency that tracks vital statistics for the United States.

Still, blacks have made notable gains in life expectancy in recent decades that demographers say reflect improvements in medical treatment as well as in the socioeconomic position of black people in America. Life expectancy at birth was up by 17 percent since 1970, far higher than the 11 percent increase for whites over the same period.

Demographers credit declining rates of AIDS and homicide, which ravaged black neighborhoods in many U.S. cities in the 1980s and ’90s, as well as reduced death rates from heart disease. Black people, who have higher rates of heart disease, have benefited disproportionately from improved treatment of it, said Samuel Preston, a demographer and sociologist at the University of Pennsylvania. But there is still a lot of room for improvement, especially to prevent heart disease in blacks, experts said.

Life expectancy for black people rose to 75 years in 2010, up from 64 years in 1970. For white people, it rose to 79 years from 72 years in the same period. In 1930, life expectancy stood at 48 for blacks and at 60 for whites.

Higher infant mortality among blacks also contributes to the gap, but less than it used to. The infant mortality rate for blacks fell by 16 percent from 2005 to 2011, compared with a 12 percent drop for whites, said Kenneth M. Johnson, a demographer at the University of New Hampshire.

Heart disease was the single biggest drag on black life expectancy, accounting for a full year of the 3.8-year difference between whites and blacks. The second-biggest factor was cancer, accounting for about eight months of the difference.

The report’s lead author, Kenneth D. Kochanek, said that 1994 was the last time his office had published a report that focused on what was driving life expectancy disparities. At that time, researchers were exploring a surprising decline in life expectancy for blacks between 1984 and 1989 that was driven in part by AIDS and homicide among black men, and AIDS and diabetes among black women.

The new report analyzed data from 2010. Preliminary statistics for 2011 show that the gap has continued to narrow to 3.7 years.

Whites have suffered a setback in a category known as unintentional injuries, which includes the surge in prescription drug overdoses that has disproportionately affected white people since the 1990s.

Blacks also had lower death rates than whites from suicide, Alzheimer’s and Parkinson’s diseases, and respiratory diseases like emphysema, as well as chronic liver disease.

Sam Harper, an assistant professor of epidemiology and biostatistics at McGill University in Montreal who has done extensive work on disparities in life expectancy, said some drivers of black disadvantage were preventable, like heart disease. Public health efforts should focus on reducing risk factors like smoking, poor diet and hypertension, he said.

Policymakers should also make sure that black people are benefiting from improvements in medical treatments for cancer and heart disease, he said. “Redoubling our efforts on these two diseases would go a long way toward reducing the black-white life expectancy gap further.”
 

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