More people smoke worldwide today than in 1980, as population growth surges and cigarettes gain popularity in countries such as China, India and Russia, researchers said Tuesday.
For instance, China boasted nearly 100 million more smokers in 2012 than it had three decades ago, even though its smoking rate fell from 30 to 24 percent in that span, said the findings in the Journal of the American Medical Association.
The rise in the number of smokers comes despite overall declines in the smoking rate in recent decades, as many people have realized the health dangers of tobacco, said the report.
The data was published as part of a series of tobacco-related articles to coincide with the 50th anniversary of the first US Surgeon General's report on the risks of smoking.
"Since we know that half of all smokers will eventually be killed by tobacco, greater numbers of smokers will mean a massive increase in premature deaths in our lifetime," said co-author Alan Lopez of the University of Melbourne.
The study, led by the Institute for Health Metrics and Evaluation at the University of Washington, measured data from 187 countries.
It found that the global smoking rate among men was 41 percent in 1980, but has since declined to an average of 31 percent.
Among women, the estimated prevalence of daily tobacco smoking was 10.6 percent in 1980, and by 2012 that had fallen to 6.2 percent.
The most rapid decrease began in the mid-1990s, but smoking has actually risen again among men since 2010, said the findings.
"This deceleration in the global trend was in part due to increases in the number of smokers since 2006 in several large countries including Bangladesh, China, Indonesia and Russia," said the study.
China had 182 million smokers in 1980, and nearly 282 million in 2012, it said.
India gained 35 million smokers -- bringing its total to 110 million -- even though the smoking rate fell from 19 to 13 percent of the population.
Russia, where about one third of people smoke, has added one million smokers since 1980.
Globally, the number of smokers has climbed from 721 million in 1980 to 967 million in 2012.
The number of cigarettes smoked annually has also risen 26 percent over the past three decades.
"The greatest health risks are likely to occur in countries with high prevalence and high consumption," said the study.
Those countries include China, Greece, Ireland, Italy, Japan, Kuwait, Korea, the Philippines, Uruguay, Switzerland and Russia, it said.
The highest smoking rates among men in 2012 were in Timor-Leste (61 percent) and Indonesia (57 percent), followed by Armenia (51.5 percent), Russia (51 percent) and Cyprus (48 percent).
Top countries for women smokers were Greece (34.7 percent) and Bulgaria (31.5 percent).
Austria had a female smoking rate of 28.3 percent, followed by France (27.7 percent) and Belgium (26.1 percent).
A larger proportion of women in France smoked in 2012 (28 percent) than 1980 (19 percent), while the rate for men went the opposite direction, declining from 42 percent to 34 percent.
In all, France had 14 million smokers in 2012, two million more people than in 1980.
The study also measured how many cigarettes on average were consumed per smoker each day in 2012, and found Mauritania was the highest with 41, or two packs a day.
Saudi Arabia's smokers averaged 35 cigarettes per day, and Taiwan's 32.
"As tobacco remains a threat to the health of the world's population, intensified efforts to control its use are needed," said the study.
The research also examined where the biggest gains against smoking have been made since 1980, particularly in countries where more than one in five people smoked.
Iceland, Mexico and Canada had the most significant declines (three percent), followed by Sweden, Norway and Denmark.
The United States, New Zealand, Australia and Britain rounded out the top 10 for the drop in smoking rates.
The US smoking rate went from 30.6 percent in 1980 to 15.8 percent in 2012. Similar trends were seen in Australia.
"Globally, there has been significant progress in combating the deadly toll of tobacco use," said Matthew Myers, president of the Campaign for Tobacco-Free Kids, who was not involved in the study.
"Where countries take strong action, tobacco use can be dramatically reduced."