While Americans are living longer than ever before, life expectancies in most of the U.S. have not kept pace with those of the longest-lived nations, a new study says.

The results show that life expectancies of people living in more than 80 percent of U.S. counties fell further behind the average of the 10 longest-lived nations over roughly the last two decades.

The main reason the U.S. has not kept up, the researchers said, is that its medical care focuses on treating people once they become sick, rather than on preventing illnesses, especially chronic conditions such as obesity and diabetes.

Life expectancies varied greatly across the nation and even between neighboring counties in some cases, the researchers said. Women's life expectancies ranged from 86 in Collier County, Fla., to 74 in several counties in Mississippi. For men, the numbers ranged from 81 in Fairfax County, Va., to 67 in Mississippi.

These differences point to disparities in health care and in other factors, they said.

"We have a system that works against people," said study researcher Ali Mokdad, of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington. "We have to have the ingredients in place that will help people live healthier if they decide to."

The vast majority of the counties that fared the worst are in the southeastern part of the country, the report said.

Why the decline

The 20 percent of counties that kept pace with the longest-lived nations have four factors in common, Mokdad said.

For one, people living in these counties have higher incomes and more education than people living elsewhere, he said. Because of this, they are more likely to seek health care advice when they're sick and to follow that advice.

They also have lower rates of behaviors known to increase health risks. Specifically, these counties have lower rates of smoking, obesity and binge drinking, he said.

Thirdly, people in these counties have better health insurance.

"We always talk about health insurance in terms of having it or not having it, but there's another layer here, Mokdad told MyHealthNewsDaily. "Not all health insurance covers preventative care. At regular checkups that's where people hear about quitting smoking and eating right."

The fourth factor the researchers identified as influencing life expectancies was the quality of health care available in an area. "Many areas in the South don't have a decent hospital or clinic," Mokdad said.

Worse for women

The report showed that women's life expectancies fell further behind other nations than men's did over the study period, from 1987 to 2007.

"Women are more affected by the obesity epidemic," Mokdad said, citing a recent Centers for Disease Control and Prevention study showing that 32.2 percent of U.S. men are obese, while 35.5 percent of women are.

Further, women are less likely to control health conditions such as diabetes, high blood pressure and cholesterol, Mokdad said.

"This surprises everybody, because women seek more health care than men in general," he said. But doctors are more likely to monitor their male patients' problems, so men have more success in controlling their conditions, he said.

To improve life expectancies, more focus needs to be put on preventative care, Mokdad said.

Changes such as requiring menus to list the calories and fat content of foods, and improvements to public outdoor spaces where people can exercise could help, according to Mokdad.

The places with the longest life expectancies, such as counties in California, Colorado, Minnesota and the Northeast, have made or are making such changes, he said.

The study was published today (June 15) in the journal Population Health Metrics.

Pass it on: Life expectancies in the U.S. vary greatly and may depend on preventative medical care.

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