By Tami Luhby

PHILADELPHIA (CNN) — The richest Americans live far longer than their poorest counterparts, a new study shows.

Men in the Top 1% can expect to live until age 87.3, nearly 15 years longer than those in the Bottom 1%, according to research by Stanford economics professor Raj Chetty and seven co-authors.

America’s wealthiest men live longer than their counterparts in any other country, while the poorest have life expectancies comparable to men in Sudan and Pakistan.

The richest women, meanwhile, have life expectancies just shy of 89 years, a full decade longer than the poorest women.

The researchers stress that fatter incomes are not the cause of longer lifespans, cautioning that simply giving people money won’t increase their longevity. Instead, longer lives may be correlated with factors such as differences in education and the health and lifestyle behaviors between the rich and poor.

The gap between rich and poor has widened in recent years. Those in the Top 5% gained about three years of life between 2001 and 2014, but those at the Bottom 5% did not see their lifespans increase.

Just how long the poor live depends greatly on where they reside. They enjoy the longest life expectancies in places with high rates of healthy behaviors, such as high levels of exercise and low prevalence of smoking and obesity. It is not significantly correlated with quality or quantity of medical care, income inequality or residential segregation.

Low-income Americans tend to live the longest — and have the healthiest behaviors — in affluent cities with highly educated residents and generous government benefits, such as New York and San Francisco.

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