Study co-author Karen Pawlish, an epidemiologist, said, "diet, obesity, physical activity and smoking may affect survival. Biological factors could explain part of the difference, but there may be other factors related to access and quality of care."

Brian Smedley, vice president and director of the Health Policy Institute at the Joint Center for Political and Economic Studies in Washington, said that "separate but unequal" health care services probably are involved.

"We know that minorities are disproportionately clustered in medically underserved communities, where many health care institutions have fewer resources to provide high-quality care," Smedley said. "Research increasingly points to differences in care that patients of color receive compared to whites. Some have called this 'medical apartheid.'"

The N.J. study "raises more questions than it answers," Smedley said. "I'd like to see research move away from describing the problem to looking at interventions that level the playing field."

press.jhu/journals/journal_of_health_care_for_the_poor_and_underserved