In one of the most comprehensive studies examining income and life expectancy, researchers find people with money live longer than those without wealth.

The median life expectancy of the richest people in Salt Lake City, Utah, is about 88 years old.

The poorest folks in Gary, Indiana, live to about 77 years, regardless of their race.

This contrast is one example of the differences in income and life expectancy appearing today in the Journal of the American Medical Association (JAMA).

Besides being political talking points during an election year, the top 1 percent, or those whose annual household incomes exceed $430,000, typically outlive those in the bottom 1 percent by an average of 15 years for men and 10 years for women, according to the new study.

The expected lifespans of the top 5 percent, on average, grew by 2.3 years for men and 2.9 years for women. For those at the bottom 5 percent, those increases were only 0.3 years for men and 0.04 years for women.

Using data from 1.4 billion tax records from 1999 to 2014, along with Social Security Administration death records, researchers at Stanford, Harvard, MIT, and the U.S. Department of the Treasury found that while higher income was associated with living longer, its effects varied across the country.

According to the latest figures from the U.S. Census Bureau, 14.8 percent of Americans—or 46.7 million people—live in poverty, a trend that hasn’t changed much over the past four years. The median annual household income in 2014, the latest year data is available, was $53,657.

Regardless of income, the most common causes of death in the United States continue to be heart disease, cancer, chronic lower respiratory disease, and accidents, according to the U.S. Centers for Disease Control and Prevention (CDC).

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Besides how much money you make, researchers found geographic differences in wealth disparity.

People with the lowest incomes have the lowest life expectancy in Nevada, Indiana, and Oklahoma and the highest life expectancy in California, New York, and Vermont.

Some of these geographic differences in the lowest income bracket were also affected by health behaviors like smoking. However, they weren’t as directly related to access to healthcare, physical environment factors, income equality, or the job market.

In low-income areas, researchers found, life expectancy was longer for immigrants, college students, and areas where government spending was higher per capita.

For example, in cities like New York or San Francisco, where there are more government-funded programs for the poor, and regulations discourage unhealthy behaviors like smoking, those in the lowest 1 percent have greater access to health and related services than in places like Las Vegas, Indianapolis, or Gary.

Barbara Wolfe, Ph.D., a professor of public affairs, economics, and population health services at the University of Wisconsin-Madison, who wasn’t involved with the study, said environment could play a role in health as well.

“When I think of cities like San Francisco or New York, I think of people walking everywhere,” she told Healthline. “Besides less pollution from cars, there’s also less industry there.”

Madison, Wisconsin, ranks eighth in life expectancy among higher earners. Wolfe said this could be due to the fact the typical high earner there has an advanced degree, something that’s been shown to positively affect a person’s lifespan.

Overall, Wolfe said, the new research not only shows how two individuals of the same age and race can live shorter or longer lives depending on where they live, but it also opens up a large data set that others can explore.

“A lot of what this study does is raise a lot of questions,” she said.

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Researchers noted these findings could be used to impact local policies, specifically those that “focus on changing health behaviors among low-income individuals. Tax policies and other local public policies may play a role in inducing such changes.”

In an accompanying editorial, Dr. J. Michael McGinnis, M.P.P., senior scholar at the National Academy of Medicine, said these nationwide findings could have a substantial impact at the community level.

“In the face of established and well-known health disadvantages for those with low incomes, the study nonetheless underscores the possibility for local initiatives to help people blunt the sharp edge of those adverse health consequences,” he wrote. “This is especially important not only because of the often remote prospects for tax and income policies required to level job and income profiles, but also because of increasing attention, incentives, and levers to support better coordinated community health initiatives.”

Angus Deaton, Ph.D., a professor of economics and international affairs at Princeton University, also penned an editorial, noting the new research likely understates the widening gap between expected life expectancies of rich and poor.

“Even if it is true that the fundamental causes of health are social and economic, there is every reason to focus on treatment and health behaviors in a country, even one as rich as the United States, where poverty is intractable and there is little immediate prospect of making the distribution of income more equitable,” he wrote.

If further research down the road shows personal unhealthy behaviors are major drivers of early mortality, Wolfe said local governments can have an impact, such as trans fats bans, increased taxes on tobacco, and other measures.

“I think it gives these communities the opportunities for innovations, and innovations that improve health,” she said. “You do want to know why some of these cities fare better.”