Smoker numbers are declining in many parts of the world, but upward trends in African and Mediterranean countries mean the global total will not change much over the next 10 years, researchers said Friday. The UN's World Health Organization (WHO) estimates that about 6 million people die around the world every year from smoking-related causes - more than 5 million from direct tobacco use and the rest from second-hand smoke.

About 80 percent of the world's 1 billion smokers, it says, live in low- and middle-income countries. An analysis published in The Lancet medical journal of trends in more than 170 countries, said smoking prevalence among men fell in 72 percent of countries measured in the decade between 2000 and 2010.

Among women, a decline was observed in 88 percent of countries. WHO member states had agreed to a voluntary target of reducing tobacco use by 30 percent worldwide by 2025 from 2010 levels, said the document. But on current trends, "only 37 [21 percent] countries are on track to achieve their targets for men and 88 [49 percent] are on track for women," it added. Rapid increases in Africa and the eastern Mediterranean would cancel many of the gains, said the authors, and projections were for "an estimated 1.1 billion current tobacco smokers in 2025."

"We project that the highest smoking quintile among men will shift from low- and middle-income countries in Europe and the western Pacific to those in Africa and the eastern Mediterranean," said the study, which did not consider smokeless tobacco use. According to the WHO, one person dies about every six seconds due to tobacco, accounting for one in 10 adult deaths. Up to half of current users will eventually die of a tobacco-related disease. A separate study carried by the same journal said that on current rates, about 3 million people will die from smoking every year in China alone by 2050. "Of great concern, about 100 million of the 0.3 billion Chinese smokers that are now younger than 30 years will eventually have tobacco-related deaths," it said.