Americans are living longer than ever, but not as long as people in 41 other countries.
For decades, the US has been slipping in international rankings of life expectancy, as other countries improve health care, nutrition and lifestyles.
Countries that surpass the US include Japan and most of Europe, as well as Jordan, Guam and the Cayman Islands.
"Something's wrong here when one of the richest countries in the world, the one that spends the most on health care, is not able to keep up with other countries," said Christopher Murray, head of the Institute for Health Metrics and Evaluation at the University of Washington.
A baby born in the US in 2004 will live an average of 77.9 years. That life expectancy ranks 42nd, down from 11th two decades earlier, according to international numbers provided by the Census Bureau and domestic numbers from the National Center for Health Statistics.
Andorra, a tiny country in the Pyrenees mountains between France and Spain, had the longest life expectancy, at 83.5 years, according to the Census Bureau. It was followed by Japan, Maucau, San Marino and Singapore.
The shortest life expectancies were clustered in Sub-Saharan Africa, a region that has been hit hard by an epidemic of HIV and AIDS, as well as famine and civil strife. Swaziland has the shortest, at 34.1 years, followed by Zambia, Angola, Liberia and Zimbabwe.
Researchers said several factors have contributed to the US falling behind other industrialized nations. A major one is that 45 million Americans lack health insurance, while Canada and many European countries have universal health care, they say.
But "it's not as simple as saying we don't have national health insurance," said Sam Harper, an epidemiologist at McGill University in Montreal. "It's not that easy."
Among the other factors: Adults in the US have one of the highest obesity rates in the world. Nearly a third of US adults 20 years and older are obese, while about two-thirds are overweight, according to the National Center for Health Statistics.
"The US has the resources that allow people to get fat and lazy," said Paul Terry, an assistant professor of epidemiology at Emory University in Atlanta. "We have the luxury of choosing a bad lifestyle as opposed to having one imposed on us by hard times."
Racial disparities. Black Americans have an average life expectancy of 73.3 years, five years shorter than white Americans.
Black American males have a life expectancy of 69.8 years, slightly longer than the averages for Iran and Syria and slightly shorter than in Nicaragua and Morocco.
A relatively high percentage of babies born in the US die before their first birthday, compared with other industrialized nations.
Forty countries, including Cuba, Taiwan and most of Europe had lower infant mortality rates than the US in 2004. The US rate was 6.8 deaths for every 1,000 live births.