If life expectancy were a marathon, you could say the United States is fading from the pack. Although everyone is living longer, the inhabitants of other industrialized nations have made more dramatic strides in life expectancy than Americans have. Australian men gained an extra six years between 1980 and 2001; Japanese women, 6.1 years. The result: Americans, once on par with countries such as Italy and New Zealand - in the middle of the pack - now rank below Spain and Greece, near the end.
Men, for example, average 74.4 years in the US, 75.6 in Spain, and 75.4 in Greece.
On the face of it, this shouldn't be happening.
Healthier nations are usually wealthier nations. The United States is the third richest of the 30 developed nations belonging to the Organization for Economic Cooperation and Development (OECD), after Luxembourg and Norway. But it now ranks 22nd in life expectancy - down from 12th for women and 18th for men in 1980.
Could the problem be inadequate healthcare spending?
No. The US spends $1 of every $7 of its gross domestic product on healthcare - far more than any other OECD nation, which typically devotes less than $1 in $10 of GDP to the sector. Per person, that works out to an extra $1,800 compared with the Swiss or $2,300 compared with the Canadians, even though both those groups live longer than Americans.
So what's at work?
One factor could be diet, according to a new study on longevity by Alicia Munnell, director of the Center for Retirement Research at Boston College, and two students, Robert Hatch and James Lee. Americans have been getting fatter, and physicians maintain that obesity often shrinks a person's life span.
"Americans don't seem to take care of themselves well," says Gary Burtless, an economist at the Brookings Institution, a Washington think tank.
On the positive side, US alcohol and tobacco consumption is more moderate than the OECD average.
Another factor holding back longevity: poverty. The quarter to a third of Americans with low incomes often have less money than the same low-income groups in several other rich countries, points out Mr. Burtless.
A third factor - inequality - exacerbates the problem. The most prosperous 10 percent of Americans receive 17 times as much income as those in the bottom 10 percent. In countries with high life expectancies among those at 65 - such as Japan, Sweden, and Norway - the top 10 percent makes only five times as much income, Professor Munnell says.
The US also struggles with inequality in healthcare. While most rich nations have universal coverage, 45 million in the US didn't have health insurance last year, according to census statistics - a rise of 5.2 million since 2000. Millions more have insurance only part of the year.
Many of those without health insurance tend to postpone medical care for chronic problems, though they may go to hospital emergency facilities in a crisis.
Thus, a better predictor of life expectancy than GDP may be the average GDP for the bottom 40 percent of the population, notes the Boston College study. Here the US falls in the middle of the pack of rich countries, rather than at the top.
And for all the money the US showers on healthcare, it's not clear that it's well-spent. Some experts see the complex American healthcare system as costly and wasteful. One estimate is that $294.3 billion, or 24 percent of total healthcare spending in 1999, went to administrative costs for insurers, employers, and providers of healthcare.
If pushing American longevity back toward the head of the class depends on changes in public policy, the prospects don't look good. Too many political obstacles get in the way.
For instance: Some 60 percent of Americans get excellent healthcare through Medicare, corporate health plans, or other plans. So they're unlikely to vote for a system providing health coverage for lower-income people, says Burtless, because it would mean higher taxes.
If longevity depends on more equal distribution of income, similar challenges arise. Those with low incomes aren't usually politically active. And the economy, after narrowing the rich-poor gap in the late 1990s, is now widening it again.
"This is a real problem for our democracy," says Burtless.