March 18--As we've known for some time, life expectancy in the United States is lower than in nearly every other developed country. What we haven't known is why -- and the reasons are starting to look far less simple than, say, a disjointed health-care system.
Although life expectancy is expressed as an old age -- 75.6 years for American men born in 2007, 80.8 years for women -- much of the difference between the United States and other nations is due to what happens earlier.
"We die more at younger ages," says Jessica Y. Ho, whose study of the gap in mortality for those under age 50 was published this month in Health Affairs. For men, those younger deaths accounted for 67 percent of the shortfall in U.S. life expectancy compared with an average of 16 other high-income nations. For women, it was 41 percent.
Ho, a doctoral candidate in demography and sociology at the University of Pennsylvania, then analyzed the data to find out which causes of death under 50 were outliers.
For men, nearly a fifth of the excess mortality was due to homicide. Transportation injuries, mainly car crashes, was close behind, followed by other injuries -- particularly drug overdoses. Perinatal mortality, such as pregnancy complications and birth trauma, accounted for 13 percent, cardiovascular diseases made up 8 percent, and other chronic conditions, 10 percent. Also contributing: suicide (4 percent), HIV (2 percent), and other communicable diseases (2 percent).
The pattern was similar for women, with some exceptions: homicide accounted for much less (7 percent) and chronic diseases other than heart much more (20 percent), as did perinatal conditions (19 percent). But suicide did not contribute to the life-expectancy gap for U.S. women under 50; that rate was lower than elsewhere.
Poverty undoubtedly plays a role in homicide, perinatal deaths, and chronic diseases, but not in many of the others.
"We seem to be doing poorly across the board," says Ho, who analyzed statistics from several international databases from 2006 to 2008. "For some of these causes of death, the health-care system is probably playing a [relatively] minor role."
There is no easy fix. Motor vehicle accidents, for example, are a significant factor in Americans' earlier deaths. But a federal study found that mortality per miles driven is no higher here than in 15 other wealthy countries. Americans simply drive more.
In a 2010 paper, Ho and Penn sociologist Samuel H. Preston compared death rates here and abroad at the other end of the spectrum -- older than 50. The United States does far better there, ranking in the top half of countries for nearly all age groups older than 75 and second from the top for men and women ages 95 to 99.
But a seemingly obvious explanation -- a lack of universal health insurance -- was not supported by the data. The pattern predated the beginning of Medicare in 1968.
The most likely reason, the researchers wrote, was "an unusually vigorous deployment of lifesaving technologies by the U.S. health-care system at very old ages."
Still, they could not rule out one other explanation: that Americans who made it through their younger years arrived at old age very, very healthy.
Contact Don Sapatkin at 215-854-2617 or firstname.lastname@example.org.
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