When it comes to predicting how long you are likely to live, the place you live matters. Life expectancy in the U.S. ranges from 85 years for women in Marin, Calif., to 72.7 years in Perry, Ky. Local longevity differences are even larger among men, who have a life expectancy in Fairfax County, Va. (81.7 years) that is 17 years longer than in nearby McDowell, W.V. (64 years), according to recent research by the Institute for Health Metrics and Evaluation at the University of Washington.
"How health is experienced in the U.S. varies greatly by locale," according to the report. "People who live in San Francisco or Fairfax County, Va. or Gunnison, Colo. are enjoying some of the best life expectancies in the world. In some U.S. counties, however, life expectancies are on par with countries in North Africa and Southeast Asia."
[Read: Best Places to Retire for Longevity.]
Counties where women enjoy the greatest longevity also include Montgomery, Md. (84.9 years), Collier, Fla. (84.6 years) and Santa Clara, Calif. (84.5 years). The life expectancy in these places is comparable to countries with the highest life expectancies in the world, including France, Spain and Switzerland. In places where males live the longest, such as Gunnison County, Colo. (81.7 years), Pitkin, Colo. (81.7 years) and Montgomery, Md. (81.6 years), life expectancy surpasses other long-lived countries like Japan and Switzerland. Places with the lowest life expectancies, such as McDowell, W.V. (72.9 years) and Tunica, Miss. (73.4 years) for women, and Bolivar, Miss. (65 years) and Perry, Ky. (66.5 years) for men, actually have shorter life expectancies than people in Algeria and Bangladesh, according to the IHME report.
The researchers speculate that the disparities in life expectancy within the U.S. likely have a variety of causes. Socioeconomic factors such as poverty and education are known to play a role in longevity. Some places might have less access to medical facilities, fewer quality health care options available to residents or more people who lack health insurance. In other places, more people engage in riskier behaviors such as smoking, a poor diet or a lack of exercise. And, of course, healthy individuals might simply move from counties with a low life expectancy into counties with higher life expectancies.
[Read: States Where People Live the Longest.]
"If you are in a county in the Southeast where obesity is very high, where you don't have health facilities, and you move to a place that has all of the above, it will improve your life," says Ali Mokdad, professor of global health at the Institute for Health Metrics and Evaluation in Seattle. "You are more likely to benefit from programs that the county has in place."
Choosing a retirement spot that helps promote healthy behaviors or one where you will be surrounded by peers also engaging in prevention could help you to live longer or remain healthier. Victor Marshall, an emeritus professor and former director of the University of North Carolina–Chapel Hill's Institute on Aging, recommends selecting a livable community with safe streets and walking paths and a wide range of options to remain physically active, including public parks, pools and tennis courts.
Should these efforts to promote health fail, you'll also want to be in a community with high-quality medical care, "ideally a university hospital affiliated with a medical school," Marshall says. Proximity to a physician who is experienced at treating older patients should be a key component in your retirement relocation decision. "It's a good idea to think, 'If something happened to me or my spouse, how would we get help?'" says James Kirkland, a professor of aging research and director of the Mayo Clinic Robert and Arlene Kogod Center on Aging. "If you are moving to an area that is very distant, if you're going to move to the top of a mountain in Alaska, you are going to have to plan on that not being the last place that you move to."
But you aren't necessarily doomed to a short life if you retire in a county with a low life expectancy, Mokdad says. "You could change your behaviors, you could stop smoking, you could decide to be physically active and eat better, and it will improve your life expectancy."