By David Brown
Washington Post Staff Writer
Thursday, June 12, 2008
Americans' life expectancy reached a record high of 78.1 years in 2006, with disparities among ethnic groups and between the sexes generally narrowing, according to government data released yesterday.
The death rates from most diseases went down, with influenza mortality falling steeply and AIDS mortality marking its 10th straight year of decline. Infant mortality in 2006 also fell from the previous year, continuing a trend stretching back nearly 50 years.
"This report has a lot of good news," said Melonie P. Heron, a demographer at the National Center for Health Statistics who compiled and analyzed the data drawn from death certificates filed with each state and the District.
The favorable trends appear to contradict reports of shortening life spans in some Americans, specifically women living in rural parts of the South and Midwest. The new report, however, did not examine mortality at that level of detail. The two trends -- overall national improvement, with certain subgroups doing worse -- are not incompatible, experts noted.
The 2006 data also provide more evidence for what demographers term the "Hispanic Paradox": As a group, Hispanics have much lower mortality rates than expected for a population of relatively less education and wealth.
The overall U.S. life expectancy of 78.1 years was up 0.3 years from 2005. Life expectancy for women was 80.7 years, and for men, 75.4 years. The disparity between the sexes -- 5.3 years -- has been declining since it peaked at about eight years in 1979.
White women had the longest life expectancy, at 81 years, followed by black women (76.9 years), white men (76 years) and black men (70 years). The gap between men and women is markedly greater in blacks (6.9 years) than in whites (five years).
Life expectancy is the calculation of how long a newborn could expect to live if the mortality rates at birth prevailed for a lifetime. Life expectancy can fluctuate from one year to the next if a large event, such as an influenza epidemic, affects the entire population, but long-term trends tend to reflect changes in the risk of death from many diseases.
From 2005 to 2006, death rates from heart disease, cancer, stroke, emphysema, hypertension, diabetes, cirrhosis of the liver, bloodstream infections, accidents and suicide all declined. The biggest drop was in influenza and pneumonia -- almost 13 percent, probably the result of a milder flu season and greater use of flu vaccine.
Heart disease and cancer, the two top killers, together accounted for 1.2 million of the 2.4 million deaths in the United States in 2006. On the list of leading causes, Alzheimer's disease rose a notch, to No. 6, and diabetes dropped a notch to No. 7.
Infant mortality in 2006 decreased slightly to 6.7 deaths per 1,000 live births. For blacks, it was 13.3, more than double that of whites. (By comparison, Angola had an infant mortality rate of 154 in 2006, one of the highest in the world -- and unchanged since 1990.)
The overall mortality rate for Hispanics in 2006 was 550 deaths per 100,000 people. For non-Hispanic whites, it was 778. For non-Hispanic blacks, it was 1,001. This is unexpected because average income and education among Hispanics (except for Cuban Americans) is below that of whites. Those two variables strongly predict health and mortality.
Researchers have offered various theories to explain the "Hispanic Paradox," first recognized in the late 1970s.
One is that it does not exist but is only the result of bad data and confusion over who is classified as Hispanic. This explanation has been largely discounted, said Elizabeth Arias, a demographer at the National Center for Health Statistics and an expert on the topic.
Other theories are that Hispanic immigrants tend to return home to die; that immigrants are inherently healthier than people in the countries to which they move; or that something in the habits or lifestyle of Hispanics in the United States is conducive to good health.
"We have found that the paradox applies more to the foreign-born," Arias said. "That leads us to believe something happens in the assimilation process that takes away the advantage."
Family support, traditional diet and relatively low rates of smoking among immigrants probably contribute to the lower mortality rate among Hispanics. But that is not likely to be the full explanation.
"There isn't just one answer. I think it is a combination of factors," she said.
A study published in April found that life expectancy for women was lower at the start of this decade than in the early 1980s. The researchers theorized that this could be the leading edge of the effect of the obesity epidemic. Another study, published in May, found a widening gap in death rates between college graduates and high-school dropouts.
Do the new statistics contradict those findings?
They might, said Ari B. Friedman, a researcher at Harvard University's Initiative for Global Health who helped write the April study. But it is also possible that some segments of the American population are faring differently than the country as a whole.
"It could well be that among certain groups, among certain places, the obesity epidemic is in decline or never existed at all, and in other places it is marching on," he said.