In Sweden, the risk of a woman dying during pregnancy and childbirth is one in 17,400, but in Afghanistan the odds are one in eight.
The report, drawn up by an eminent panel of experts forming the WHO's Commission on the Social Determinants of Health, found that, in almost all countries, poor socioeconomic circumstances equated to poor health.
The differences were so marked that genetics and biology could not begin to explain them.
The authors write: "(The) toxic combination of bad policies, economics, and politics is, in large measure responsible for the fact that a majority of people in the world do not enjoy the good health that is biologically possible."
LIFE EXPECTANCY AT BIRTH
Selected countries (2006)
Life expectancy at birth (years)
The report calls for governments to consider how all their policies impact on health.
It says that it is entirely possible to reduce health inequality within a relatively short period of time.
But it warns that, without action, injustice and inequality will only increase.
Sir Michael Marmot, chairman of the commission, told BBC Radio 4's Today programme said : "There are examples where health inequalities have narrowed but, in too many cases, we have seen a widening.
"But that means the magnitude of inequalities is flexible - if the gap can widen, it can get narrower."
"In the UK, we have seen an improvement in people's health over the last eight years."
But Sir Michael said the benefits to the worst off had not been as significant as those seen among the best off.
He said: "The key message of our report is that the circumstances in which people are born, grow, live, work, and age are the fundamental drivers of health, and health inequity."
"We rely too much on medical interventions as a way of increasing life expectancy."
"A more effective way of increasing life expectancy and improving health would be for every government policy and programme to be assessed for its impact on health and health equity; to make health and health equity a marker for government performance."
"People need the opportunity, the possibility, to take control of their lives - but the conditions need to be right to allow them to do that."
The report highlights education, affordable housing, management of access to unhealthy foods and social security protection as key.
It also said that governments should take action to ensure a living wage for workers, and working conditions that reduce work-related stress and ensure a healthy work-life balance.
Ann Keen, health minister for England, said the recent Darzi review had identified the reduction of health inequalities as a key priority for the NHS, and tackling the social factors driving the problem was a core plank of government policy.
She said: "The UK is at the forefront of tackling health inequalities, but the challenge of reducing the gap in life expectancy is still very much an issue."
Norman Lamb, Liberal Democrat health spokesman, said: "The WHO makes it clear that while healthcare has improved, it is the rich who are reaping the benefits.
"It is shocking and disgraceful that this contrast can exist in modern Britain."
Shona Robison, Public Health Minister for Scotland, said: "This government has put tackling health inequalities at the forefront of the future health agenda, and importantly, at the heart of every government policy whether that be housing, employment, communities or education.
"Until now, social ills such as crime, poor health and poverty have held too many people back in Scotland."
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