Researchers at the Institute for Health Metrics and Evaluation (IHME) at the University of Washington and Imperial College London conducted a large new study of lifespans worldwide.

They found that 80% of countries fell in their life-expectancy rankings measured against the average of the world’s 10 leading countries, a number known as the “international frontier.”

“When compared to the international frontier for life expectancy, U.S. counties range from being 16 calendar years ahead to more than 50 behind for women. For men, the range is from 15 calendar years ahead to more than 50 calendar years behind. This means that some counties have a life expectancy today that nations with the best health outcomes had in 1957,” said Dr. Christopher Murray, IHME Director and one of the paper’s co-authors.

According to the study authors, the causes cited are obesity, smoking, and other preventable factors. Appalachia, the Deep South, and Northern Texas had the lowest average lifespans.

The lowest life expectancy for women in the U.S. were five counties in Mississippi, where expected lifespan is lower than 74.5 years and 67 years for men. Women have the longest life expectancy in Collier, FL, at 86 years, while men have the longest in Fairfax County, VA, at 81.1 years, which is ahead of the Japanese national average.

Published in Population Health Metrics, the title of the study is “Falling behind: life expectancy in US counties from 2000 to 2007 in an international context.”