FOR as long as anyone has kept statistics, and with a range of speculative explanations, what has always been irrefutable is that white people in America live longer than black people.
Called the black-white life expectancy gap, it has widened, narrowed and widened again during the last 100 years. Now that gap has narrowed to a historically low level, from a 7.1-year gap in 1993 to a 5.3-year gap in 2003, the latest year for which national statistics are available.
In a study in last week's Journal of the American Medical Assn., researchers from Canada, England and the U.S. parsed the numbers from the National Center for Health Statistics to explain the trend -- and why a longevity difference remains.
They found some bad news, some good news and considerable challenges ahead in bringing African American life expectancy in line with that of whites. "With a century-long view, it looks like a lot of progress," says Sam Harper, an epidemiologist at McGill University in Montreal and lead author of the study. "But there still remains a pretty substantial gap in 2003. Despite the improvements we've seen in homicide and HIV, the gap in heart disease still remains."
That, he says, is the chief culprit behind the shorter life expectancy for black people.
Although HIV/AIDS, which disproportionately affects black people in America, added to the gap until 1996, life-saving drugs then became available and more people -- regardless of race -- began living with it as a chronic disease.
The high homicide rate of the 1980s also disproportionately affected young African Americans, contributing to an overall decrease in black life expectancy. The homicide death rate for all Americans has dropped from 10.4 per 100,000 in 1980 to 5.9 per 100,000 in 2004. While young black men, ages 15 to 24, are still victims of homicide in staggeringly high numbers -- 77.6 per 100,000 in 2004 -- those numbers have fallen from a high of 137 per 100,000 in 1990.
African Americans continue to face some sobering health challenges. Among them, the death rate from heart disease is about 30% higher than whites, according to the Centers for Disease Control and Prevention. The prevalence of diabetes is about 70% higher, and diabetes significantly increases the risk of heart disease.
"African Americans have greater coronary disease, it happens earlier, and the mortality rate is higher," says Dr. Karol Watson, cardiologist and co-director of preventive cardiology at UCLA and spokeswoman for the American Heart Assn. "There are a whole lot of theories about why, but no one knows for sure."
High blood pressure is the leading risk factor for heart disease in African Americans, and some speculate that the cause is genetic. But while American blacks have higher rates of hypertension -- 41% of blacks compared with 27% of whites-- blacks living in African countries have few blood pressure problems, casting doubt on a genetic link.
Doctors know from their practices that black people often respond differently to some medications, yet there's a dearth of scientific information on why. Cholesterol-lowering drugs, studied primarily in white people, lower cholesterol in people of all races, but they bring the numbers down less in black patients, Watson says. ACE inhibitors are also less effective at lowering blood pressure in blacks than in whites.
A 10-year study called the Multi-Ethnic Study of Atherosclerosis, begun in 2000 by the National Heart Lung and Blood Institute, was begun to answer some of those questions and could eventually do so. "So far, every bit of data we have on treating African Americans is extrapolated from studies of whites," Watson says.
When it comes to race, disease theories can become controversial. "Black women aren't getting mammograms at the same rate as white women," says Faith Mitchell, senior program officer on health disparities at the Institute of Medicine. "Is it that they don't know they should be doing breast self-exams? Are they leery of doctors? Are they being offered the appropriate tests?"
Most controversial, do doctors treat black people differently than they treat white people? "It's tricky," Mitchell says. "No one is going to stand up and say, 'Yes, I make distinctions based on gender and race.' But there's a continuing pattern of care that's hard to explain."
Studies have shown that black people with diabetes, for example, are more likely to have limbs amputated than are whites, even when the disease shows similar progression.
And one classic 1997 study, by Dr. Kevin Schulman of Georgetown University, created videotapes using actors who were men and women, black and white. All of them feigned similar heart disease symptoms. When the tapes were shown to 720 physicians, researchers found that women and blacks were less likely to be referred for cardiac catheterization than were men and whites.
The life expectancy gap is getting smaller, but it persists.
"What our study shows is that we can do a better job," Harper says. "We already know a lot about how to prevent and treat cardiovascular disease. If we can do a better job focusing on how to treat heart disease in minority communities, we can continue to close the gap."