Millions of women in developing countries risk disease and early death in the coming decades as their rising economic and political status leads them to smoke more, researchers said on Tuesday.
An analysis in 74 countries found that men are five times more likely to smoke than women in countries with lower rates of female empowerment, such as China, Indonesia, Pakistan, Saudi Arabia and Uganda.
In countries with relatively high female empowerment, such as Australia, Canada, Norway, Sweden and the United States, this gap is small and women smoke almost as much as men do.
Douglas Bettcher, director of the World Health Organization (WHO) tobacco free initiative, said the findings showed the need for authorities to act quickly to curb smoking rates among women, particularly in poorer countries.
"The tobacco epidemic is still in its early stages in many countries but is expected to worsen," he said in a statement with the study, which was published in the WHO Bulletin.
"Strong tobacco control measures such as bans on tobacco advertising are needed to prevent the tobacco industry from targeting women."
Tobacco kills up to half its users and is described by the WHO as "one of the biggest public health threats the world has ever faced." The annual death toll linked to tobacco is more than five million, experts say, and could rise beyond eight million by 2030 unless action is taken to control smoking.
The study estimated that men smoke nearly five times as much as women worldwide, but the ratios of female-to-male smoking prevalence rates vary dramatically.
In China, for example, 61 percent of men are reported to be current smokers, compared with 4.2 percent of women, while in many rich nations roughly equal numbers of men and women smoke.
Women's empowerment is measured by the United Nations Development Program using data such as representation in parliament, voting rights and comparisons of male and female income.
"Our study makes a strong case for implementing gender-specific tobacco control activities ... such as more higher tobacco taxes, more prominent graphic health warnings, smoke-free laws, and advertising and promotion bans," said Geoffrey Fong from the University of Waterloo in Ontario, Canada, who led Tuesday's study.
His coauthor Sara Hitchman said authorities should look closely at "the ways in which the tobacco industry is capitalizing on societal changes to target women, such as marketing cigarettes to women as a symbol of emancipation."
The two authors also said a useful step could be to monitor how price and tax measures affect uptake of smoking among women in countries where tobacco is not yet widely used by them.
"Further research into patterns of uptake could help governments take more effective action and reduce adoption rates for smoking among women in the future," said Hitchman.