The seriousness of the epidemic of tobacco use in half of the world's population has been revealed.

According to experts, there are approximately 852 million tobacco consumers (661 million smokers and 247 million smokeless tobacco users) in Ireland, the UK, USA, and 13 other developing countries.

There are alarming patterns of tobacco use, even after years of global efforts to control it, with nearly half of men in developing countries still using tobacco. Meanwhile, women are increasingly starting to smoke at younger ages and there are low quit rates for both sexes in most countries.

Experts have called for a redouble of efforts to control the use of tobacco worldwide.

According to the study, major disparities remain in the use of tobacco and access to effective policies and treatments to limit its use.

"Although 1.1 billion people have been covered by the adoption of the most effective tobacco-control policies since 2008, 83% of the world's population are not covered by two or more of these policies", explains Gary Giovino from the University at Buffalo School of Public Health and Health Professions in New York who led the research.

"Our findings come at a crucial point in tobacco control, several years after the ratification of the Framework Convention on Tobacco Control (FCTC)... and reinforce the need for effective tobacco control."

Researchers compared tobacco use and cessation in adults (aged 15 years or older) from 14 countries of low and middle income (Bangladesh, Brazil, China, Egypt, India, Mexico, Philippines, Poland, Russia, Thailand, Turkey, Ukraine, Uruguay, and Vietnam), that account for most of the disease burden from tobacco use.

Nationally representative data from the UK and the USA were also included for comparison.

The overall picture shows disproportionately high rates of tobacco smoking among men (41% vs 5% in women) and wide variation in smoking prevalence between GATS countries, ranging from about 22% of men in Brazil to over 60% in Russia, and from 0.5% of women in Egypt to almost 25% in Poland. Women in the UK (21%) and the USA (16%) also reported some of the highest smoking rates.

With an estimated 301 million tobacco users, China has more tobacco consumers than any other country, closely followed by India with almost 275 million. The majority of tobacco users (64%) smoke manufactured cigarettes, although smokeless tobacco use (eg, loose-leaf chewing tobacco and snuff) is particularly common in India (206 million users) and Bangladesh.

Of particular concern is the rise in tobacco use among women at younger ages.

Quit rates are very low in most countries, with less than 20% of adults who had ever smoked in China, India, Egypt, Bangladesh, and Russia saying they had quit.

Quit ratios were highest in the UK, USA, Brazil, and Uruguay with over 35% of ever smokers saying they had stopped.

The research was undertaken using data from the Global Adult Tobacco Surveys (GATS) undertaken between 2008 and 2010.

Commenting on the research, Jeffrey Koplan from Emory University in the USA and Judith Mackay from the World Lung Foundation in Hong Kong, said: "With behaviours and lifestyle in flux globally and marketing rampant, we can expect initiation of tobacco use to begin at younger ages than at present, and pressures on young women to smoke to increase.

"Hopefully, with successful control efforts, there will be an increase in attempted and successful quit rates. Thus, repeated GATS or their equivalent will be an essential element of tobacco control...The main challenge is how to translate the findings from GATS and other surveys into health policy."

The new research, published in The Lancet special issue on respiratory medicine.