Women Life Expectancy Declining in Half of All U.S. Counties to 81 Year Average

Life expectancy among women under 75 years and living in certain parts of the U.S. is steadily declining, according to new research published in the journal "Health Affairs."

The findings indicate that in almost half of the country's counties, women under the age of 75 are dying at rates higher than before.

Experts suspect the shorter life spans were due to increased smoking rates and obesity rates in those particular regions of the country. However, researchers are quick to add there are still too many uncertainties to definitely know what the true causes really are.

The research marked the first attempt of its kind to identify the trend, which is especially evident among low-income white women.

Researchers note the average lifespan for a girl born in 2013 is 81 years, compared to 76 for boys.

The study analyzed the mortality rates in 3,141 counties across the country over a period of 10 years. Through the decade, it was found female mortality rates rose in 42.8 percent of the counties, while male mortality rose in only 3.4 percent of the counties.

Given the fact that some of the counties are not that heavily populated, the researchers calculated five year averages to try and be as accurate as possible. In addition, they adjusted their results to account for factors such as education and income.

A previous study conducted by researchers from the Institute for Health Metrics and Evaluation found that life expectancy in  80% of all counties in America had fallen further behind the life expectancy average of the top 10 countries in the world. That study also found females were living less years.

To underscore the connection the study discovered between education and longevity, the data showed life expectancy appeared to increase among educated and affluent women while it fell among those who hadn't finished high school.

"I think the most likely explanation for why mortality is getting worse is those factors are just stronger in those counties," said Dr. Christopher Murrayfrom the University of Washington. "We shouldn't jump to the conclusion that more people are getting sicker in these geographic areas than previously."

Some experts think the data indicates a migration of healthy women out of rural areas, relocating to more urban locations where mortality rates have gone down.

Murray, however, notes migration didn't impact male mortality rates.