Study shows declining life span for U.S. women

A new study offers more compelling evidence that life expectancy for some U.S. women is actually falling, a disturbing trend that experts can't explain.

The research found that women age 75 and younger are dying at higher rates than previous years in nearly half of the nation's counties, many of them rural and in the South and West.

This is the latest study to spot the pattern, especially among disadvantaged white women. Some leading theories blame higher smoking rates, obesity and less education, but several experts said they simply don't know why.

Women have long outlived men, and the latest numbers show the average life span for a girl born today is 81, and for a boy, it's 76. But the gap has been narrowing, and data from the Centers for Disease Control and Prevention have shown women's longevity is not growing at the same pace as men's.

The researchers, David Kindig and Erika Cheng of the University of Wisconsin, looked at federal death data and other information for nearly all 3,141 U.S. counties over 10 years. They calculated mortality rates for women age 75 and younger.

Many counties have such small populations that even slight changes in the number of deaths produce dramatic swings in the death rate from year to year. To try to stabilize the numbers, the researchers computed some five-year averages.

They found that nationwide, the rate of women dying younger than would be expected fell from 324 to 318 per 100,000. But in 1,344 counties, the average premature death rate rose, from 317 to about 333 per 100,000. Deaths rates rose for men in only about 100 counties.