The death rates of poor people who live in rich neighbourhoods in the US are higher than those who live in disadvantaged areas, a study says.
The trend is not being repeated in the UK, say experts
Researchers studied 8,200 people for 17 years across California, the American Journal of Public Health reported.
The Stanford University Medical Center team said the likely cause was rich areas drained people's resources and had a negative psychological effect.
Experts said it showed the polarised nature of US society.
The researchers found that after 17 years, 19 out of every 1,000 women of low socioeconomic status who lived in wealthier neighbourhoods had died, compared with 11 of every 1,000 from poorer neighbourhoods.
The trend was similar but less dramatic in men.
The team found that age as well as a number of risk factors, such as obesity and smoking, did not account for the results.
They also found that access to neighbourhood goods and services did not explain the findings.
Report author Professor Marilyn Winkleby said in many ways the results were surprising.
But she added the cost of living in an affluent neighbourhood could leave poor people with little disposable income to spend on essential goods and services, such as health care and healthy food.
She also said living in an affluent neighbourhood as a poor person could have a negative psychological impact.
"You look out every day and you're bottom of the social ladder."
Professor Danny Dorling, an expert in health inequalities at Sheffield University, said the reasons suggested by the report were "quite likely".
But he added: "We are not seeing anything like this in the UK. The poor and rich tend to be quite segregated here, with the exception of London, where the poor living near to the rich tend to be young migrants who are fit and healthy anyway.
"There is also the issue of American society, its health system and the fact that they tend to leave poor areas to get worse, whereas we bulldoze them and rebuild them here.
"Hospitals also tend to be located in inner city areas... and coupled with the fact care is free in the NHS, the US is more polarised."