Location and income may impact life expectancy, a new study suggests.

The link between income and life expectancy varies from one location to another within the United States, said researchers from Stanford University.

The poor tend to have shorter lifespans than those who are richer based on more than a billion Social Security and tax records. The study has also pointed out five U.S. cities with the worst life expectancy.

Five Cities With Worst Life Expectancy

Cities where residents in the lowest income group live had the shortest life expectancy. Two cities each from Indiana and Oklahoma were included.

The lowest life expectancy age was from Gary, Indiana with 77.4 years. The four other cities are Indianapolis in Indiana; Las Vegas in Nevada, Oklahoma City and Tulsa in Oklahoma, all have a life expectancy of 77.6 years.

The reason behind this trend is unclear because it is hard to determine why poor residents in these five cities were more at risk than those in other cities, the researchers said.

Why Is This So?

They found that lower life expectancy is not linked to reduced access to medical care or pollution levels. Instead, they believe that residents belonging to the lowest income quartile of other cities have more access to resources than those in depressed cities.

"We don't know exactly why that is, but what I find striking is that the results go against the view that the poor do better in cities that are more affordable with less inequality," said Raj Chetty, a senior fellow at the Stanford Institute for Economic Policy Research.

In some places, the poor are actually doing as well as having much in terms of life span as those who are rich. In other places, however, the poor are living shorter lives today than they did in the past.

"The places with shorter life expectancy tend to be places with higher rates of smoking, higher rates of obesity and lower rates of exercise," he added.

Highest Life Expectancy For Low Income Residents

The cities with the highest life expectancy among those in the lowest income group are New York City in New York with 81.8 years, Santa Barbara in California with 81.7 years, San Jose in California with 81.6 years, Miami in Florida with 81.2 years and Los Angeles in California with 81.1 years.

In the high-income group of cities the life expectancy spans from 87.8 years to 84.1 years at the least.

The study was published in the Journal of the American Medical Association.

Photo: Jake Stimpson | Flickr