London School of Hygiene & Tropical Medicine

The difference in death rates between countries is increasing, a new report has revealed.

Researchers found that the late 1980s saw a switch from global convergence of life expectancy at birth to divergence even though global mortality rates continued to fall.

And they warned that progress in reducing mortality rates between many populations around the world is now more than offset by the increases in adult mortality seen in other nations.

Kath Moser of the London School of Hygiene & Tropical Medicine, lead author of the report, said: "Since the late 1980w, the world has not only failed to become a more equal place in terms of mortality, it has actually become less equal.

"Although in one sense, the world has become a better place as mortality declines, in another way it has become worse as the distribution of life expectancy at birth worldwide has started to diverge."

Researchers found that the impact of HIV/AIDS in sub-Saharan Africa and the major health crisis in the former Soviet Union had played a huge role in reversing the previous worldwide trend towards convergence in life expectancy.

Between the early 80s and the end of last century, a total of 24 countries - accounting for 7.6 percent of the world's population - experienced drops in life expectancy.

These included 16 nations in sub-Saharan Africa, the rest being in Asia and the former Soviet Union. In eight of the countries, all in Africa except North Korea, average life expectancy fell by more than five years.

Researchers used a ground-breaking method to measuring mortality convergence across the world. They looked at death rates and population data from 1950-2000 for the 152 countries with a population of 1m or more, which covers 99.7 percent of the world' s population.

The report, published in this month's Bulletin of the World Health Organisation, also showed that most countries which experienced a fall in life expectancy had improved infant mortality rates over the periods examined.

Ms Moser said that the Millennium Development Goals adopted worldwide a few years ago focussed on reducing mortality among children aged less than 5 years old.

But she added: "Mortality among children is not the main factor behind the global divergence in life expectancy at birth. Our analysis suggests that adult mortality should be given greater emphasis as a global public health priority than is the case in the Millennium Development Goals."

Ms Moser said: "So far this divergence is relatively small and has been of limited duration compared with the earlier convergence. What is not clear is whether the divergence will continue or whether it will be reversed."

And she warned: "Future global progress should be judged not only in terms of whether overall life expectancy continues to improve, but also according to whether mortality convergence can be re-established and accelerated.

"There are also worrying signs that, unless action is taken, we may for the first time in decades see global divergence in childhood mortality. If we want to create a more equitable world it is essential that policy makers address these serious developments."