A black man living in a high-crime city can expect to live 21 fewer years than a woman of Asian descent in the United States. The man's life expectancy is closer to that of people living in West Africa than it is to the average white American.

The new study also found that African-Americans who live outside inner cities and the rural South have a life expectancy five years shorter than the vast majority of urban and suburban whites.

The differences in U.S. life expectancy among the eight demographic groups identified in the study are as wide as the difference between Iceland and Uzbekistan. The report, based on 2001 data, reveals a United States that is pocked by places where millions of adults face a risk of premature death like that in parts of the developing world.

Those differences -- the most obvious sign of the health disparities that have captured the attention of policy-makers -- have not changed in two decades.

``I think it's pretty fair to say we're failing,'' said Christopher Murray, a researcher at the Harvard School of Public Health.

One of the reasons for the disparities, Murray says, is that the biggest difference in mortality is seen among people in middle age. That part of the population has not been a major focus of new investment in government health programs.

Instead, children and the elderly -- among whom the disparities are less severe -- have been the principal targets of new and innovative health spending.

Murray said the most important contributors to increased mortality, in order of importance, are tobacco, alcohol, obesity, high blood pressure, high cholesterol, diet and physical inactivity that take a toll on people ages 15 to 65.

The study, by Majid Ezzati, also of Harvard, along with Murray and five other researchers, is published in the Public Library of Science's online journal, PLOS Medicine.

As previous studies have shown, Asian-Americans have by far the longest life expectancy -- 87.4 years for women and 82.1 for men. Black urban men have the shortest, 66.7, followed by Southern rural black men, at 67.7. American Indian men in the West are next, at 69.4.

The study found that the longest-living whites were not the relatively wealthy. They are edged out by low-income residents of the rural Northern Plains states, where the men tend to reach age 76 and the women 82.

Yet low-income whites in Appalachia and the Mississippi Valley die four years sooner than their Northern neighbors.

Curiously, Asian-American women in the United States -- many of whom are second-generation and have spent their whole lives here -- have a life expectancy that is three years longer than Japanese women, who, as a national group, are the longest-living in the world. Previous research suggests that people of Asian background lose their ``survival advantage'' after they are in the United States for a long time and have adopted a U.S. diet and habits, but the new study suggests that is not happening with those women.

Among states, Hawaiians are living longest, to about 80 for men and women. The other states with longer-living residents -- to about 78 -- are, ranked from No. 2 to No. 10: Minnesota, Utah, Connecticut, Massachusetts, New Hampshire, Iowa, North Dakota, Rhode Island and California.

The District of Columbia is the worst place to live, with a life expectancy of 72 years. It is followed by Mississippi, 73.6 years, Louisiana, 74.2 years, Alabama, 74.4 years, and South Carolina, 74.8 years.