WEDNESDAY, June 15 (HealthDay News) -- A full 80 percent of U.S. counties lag behind other leading nations in terms of life expectancy, and the gap is getting bigger, according to a new county-by-county report.

Life expectancy in some areas of the United States is actually decreasing, whereas it's increasing in the world's 10 leading nations, the report found.

"The gap between the U.S. and the 10 countries in the world that have the best life expectancies -- places like Australia, Canada, Sweden and Japan -- is widening," said Dr. Christopher Murray, lead author of the new report, published online June 15 in Population Health Metrics. "There's really no reason we can't keep pace with those other countries. We spend more on health care. We have the best health research in the world. That was a real shock."

Overall, life expectancy in the United States edged up 4.3 years for men and 2.4 years for women between 1987 and 2007, but that remains short of the gains other nations are experiencing.

In 2007, life expectancy for American women, at 80.8 years, ranked 33rd in the world. The life expectancy for American men, at 75.6 years, ranked 36th.

In some U.S. counties, the life expectancy is more than 50 years less than that of other developed nations. However, in other U.S. counties, life spans are an average of 15 to 16 years longer than the best of other nations.

But the comparison between individual U.S. counties and other nations may not be an entirely fair one because the life expectancy formula used for other countries creates "an unusually long-lived frame of reference compared to the U.S.," said S. Jay Olshansky, a professor of public health and a senior research scientist with the Center on Aging at the University of Illinois at Chicago. "It would have made more sense to compare U.S. county life expectancies with county equivalents in other countries."

The county-by-county comparison within the United States may be even more disturbing, he said.

Black men have the lowest life expectancy in the United States, at 70 years, the study found, and Asian-American women have the highest, at 85.7 years. White women live an average of about 81 years.

Women in five counties in Mississippi had the lowest average life span, below 74.5 years -- lower than women in Honduras or El Salvador.

Five Mississippi counties also ranked poorly for men. With a life expectancy of less than 67 years, men there had the lowest life expectancy in the United States and fell behind Brazil and the Philippines.

"A life expectancy of 65.9 for males in one county in the U.S. places that population's longevity prospects in the context of parts of sub-Saharan Africa," Olshansky said.

On the flip side, women living in Collier County, Fla., have more to look forward to. The report found that women there live an average of 86 years, longer than in France, Switzerland or Spain.

Men in Virginia's Fairfax County have the longest life expectancy in the United States, at 81.1 years, higher than in Japan or Australia.

Sometimes great disparities live almost literally right next door to each other. The average life expectancy in Yuma, Ariz., has increased 8.5 years for men since 1987, but in neighboring La Paz County, people can expect to live one year less than they did 20 years ago.

"Disparities have long been known to occur because of variation in education and behavioral risk factors, which are also mediated by race," Olshansky explained.

Reducing tobacco use, especially among women, along with lowering obesity and blood pressure rates, would go a long way toward solving the problem, according to the report's authors.

In fact, if these three factors plus blood sugar levels were better controlled, they said, life expectancy would increase about five years for women and four years for men.

But that's not happening, so measures to improve these risk factors increasingly need to take place on a community level, they added.

"Communities [can] make it easier to have a healthier diet, make it harder to smoke by taxing cigarettes and make it more difficult to expose people to secondhand smoke," said Murray, who is director of the Institute for Health Metrics and Evaluation at the University of Washington in Seattle.

Better primary care would likely also result in better outcomes for blood pressure and cholesterol, he said.

"There's no intrinsic reason why the U.S. can't be making as much progress as other countries and no reason we can't be the best," Murray said. "This is an incredible situation where life expectancy is getting worse in many places, especially for women."

The report, entitled Falling behind: life expectancy in US counties from 2000 to 2007 in an international context, includes life expectancy data from 1987 through 2007 for 3,138 U.S. counties and 10 cities.

More information

The U.S. Centers for Disease Control and Prevention has more on healthy aging.