单项选择题

TEXT D
If life expectancy were a marathon, you could say that the United States is fading from the pack. Al though 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 a par with countries such as Italy and New Zealand—in the middle of the pack--now rank below Spain and Greece, near the end.
On the face of it, this should not 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^①. Americans have been getting fatter, and physicians maintain that putting on weight often shrinks a person’s life span.
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. Burt less.
A third factor—inequality—worsens 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 in come as those in the bottom, Professor Munnell says.
The US also struggles with inequality in healthcare. While most rich nations have universal coverage, 45 million in the US did not have health insurance last year, according to census statistics—a rise of 5.2 million since the year of 2000^②. 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 predicator of life expectancy than GDP may be the average GDP for the bottom 40 per cent 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.
Why does the author say inequality makes the problems worse