A new study offers more compelling evidence that life expectancy for some US 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 expectancy 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 several experts said they simply don't know why. Trying to figure out why is "the hot topic right now, trying to understand what's going on," says a Harvard sociologist. 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 phenomenon of some women losing ground appears to have begun in the late 1980s, though studies have begun to spotlight it only in the last few years. (Read more life expectancy stories.)