About as many people are now dying from smoking in the developing world as in the industrialised nations, according to the most thorough estimate to date of global deaths caused by tobacco.
The research, published this week in The Lancet medical journal, concludes that 4.83 million people died from smoking in 2000 -- 2.41 million in the developing countries and 2.42 million in rich nations.
Governments -- especially those in developing countries -- will likely use the study to build anti-smoking health policies, according to experts.
"Policies and legislative activities within countries frequently only happen when it becomes obvious that the epidemic is actually happening in that country," said Dr Michael Thun, head of epidemiology at the American Cancer Society, who was not involved in the study.
A study last month found that in India, smoking mainly kills through tuberculosis rather than through lung cancer as in the West.
"Smoking kills people in different ways in different countries but what is common is this very high toll from smoking, wherever it becomes prevalent," said Thun.
The latest study, conducted by Alan Lopez at the University of Queensland in Brisbane, Australia, and Majid Ezzati of the Harvard School of Public Health, used findings from the more recent studies to build a global picture.