A new study says America's wealthy live longer than its poor, which is hardly surprising. But it also says low-income people live longer in certain places—like affluent cities including New York and San Francisco, NPR reports. Why isn't clear, but lead study author Raj Chetty of Stanford University was surprised. "I would have thought these very expensive big cities ... for most poor would be stressful and would be places with poor health among the poor, but that's not at all what these data suggest," he tells CBS News. Media reports note that local health policies may have an effect (New York City and San Francisco banned trans fats and restricted tobacco use early on), and Chetty agrees that "thinking about policies that change health behaviors at a local level is likely to be important."
The study's other findings highlight the crushing effects of inequality. By analyzing over a billion tax and Social Security records, the Stanford researchers found that the richest 1% of men live roughly 15 years longer than the poorest 1% of men. And in the 21st century, life expectancy has risen 2.3 years for the richest 5% of men and 3 years for the richest 5% of women, while the poorest 5% of Americans saw hardly any improvement. An overall three-year boost in lifespan, the Washington Post notes, is about the difference we'd expect to see from curing cancer. As Chetty puts it, "The poorest men in America have a life expectancy comparable to those living in Sudan and Pakistan." (One study says that eating like the Japanese will make you live longer.)