LIFE SPAN FALLING

New research shows that women 75 and younger are dying earlier in nearly half the nation’s counties.

A study found that death rates for women under age 75 increased in nearly half of U. S. counties and some theories blame higher smoking rates and higher unemployment.

NEW YORK — 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 latest 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. Curiously, for men, life ex- pectancy has held steady or improved in nearly all counties.

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

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

The study, released Monday by the journal Health Affairs, found declining life expectancy for women in about 43 percent of the nation’s counties.

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, sometimes called “premature death rates,” because many of those deaths are considered preventable.

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.

Some of the highest smoking rates are in Southern states, and the proportion of women who failed to finish high school is also highest in the South.