Though it has been long known that poverty is a risk factor for many diseases and premature death, there is also evidence that this “relative deprivation” is consequential to health in ways just beginning to be understood. “The broader observation is that income inequality itself leads to poorer health,” said Wolfe, noting that this has implications for the wealthy and middle-class as well. “We might expect that those at the bottom would be worse off, but evidence suggests it is also bad for high-income residents.”

Ichiro Kawachi, a professor of epidemiology at Harvard University, has been a leading voice in calling attention to the health effects of income inequality. He has posited that social cohesion is eroded by a “pollution effect”: Wealth is sucked into private enclaves, gated subdivisions and neighborhoods where the 1 percent buy out of the health-care system and have less reason to interact with or care about the other 99.

At the same time, it is becoming increasingly clear that most diseases are affected, if not caused, by stress. Psychosocial circumstances modulate everything from blood pressure to immune functioning to sleep. The major stressors across American society bear on finances. The effects of social immobility are made worse with greater income segregation; the apparent ladder that seemed impossible to climb just keeps getting longer.

“Income inequality has pathways through which it can impact health, no question about it,” said Subu Subramanian, a professor of population health and geography at Harvard. “The concern for a society like the United States is more in relation to relative deprivation—in addition to absolute deprivation. Whether it’s through increasing premiums, or shrinking investment in the community, or disenfranchisement or displacement.”

The idea is that once some basic needs are met, the visceral effects of being non-wealthy don’t deal much in absolute numbers. Wealth matters to health in that it informs perceptions of ourselves, and our sense of growth and mobility. Known as John Henryism, it is well documented that when we strive against stacked odds, we pay with our health.

“It’s not really ‘Does that person have nicer shoes than I do?’ stuff,” said Subramanian. “It’s the big-ticket sense of place and value: Which neighborhood can I afford to belong to, and so what sort of life can I provide for my family?”

In that sense, he said the “I don’t have very much” phenomenon is now kicking in even among the upper-middle class, in the $80,000 to $100,000 income range. This includes people who can afford to live in big cities, like New York or San Francisco, but for whom there are clear lines as to which neighborhood they can afford.

The pace at which gentrification and income segregation are happening mean there are places where people making that much will be priced out and have to move, and even though they are far from poverty, they experience relative deprivation. Most people are fine if they don’t have the nicest house on the block, or if they don’t live in their ideal neighborhood. But as soon as it becomes impossible to live in that neighborhood at all, and large swaths of major cities are simply out of the question, the social fabric is torn, social capital collapses.