Nearly 1 billion people around the world light up cigarettes every day, a new study finds.
The findings signal to experts that despite progress in reducing the number of smokers, more work is still needed to target tobacco use, the researchers said.
Interestingly, the researchers found that although the percentage of people who smoke has declined, the overall number of smokers has actually increased, thanks to population growth, according to the study, published April 5 in the journal The Lancet.
In other words, because there are more people on Earth, there are more smokers. But compared to the overall population, the percentage of people who smoke is lower than it was 25 years ago. [Kick the Habit: 10 Scientific Quit-Smoking Tips]
"Growth in the sheer number of daily smokers still outpaces the global decline in daily smoking rates, indicating the need to prevent more people from starting the tobacco habit and to encourage smokers to quit," senior study author Emmanuela Gakidou, a professor of global health at the Institute for Health Metrics and Evaluation at the University of Washington, said in a statement.
In the study, the researchers looked at data on smokers in 195 countries and territories between 1990 and 2015. Overall, they found that approximately 933 million people smoked each day in 2015. The world's population was 7.2 billion in 2015, up from 5.3 billion in 1990, according to U.S. Census statistics.
More than 80 percent of these daily smokers in 2015 were men, according to the study. The researchers found that worldwide, 1 in 4 men smoked every day, compared with 1 in 20 women. The daily smoking rates in men decreased from 35 percent in 1990 to 25 percent in 2015, and the daily smoking rates in women decreased from 8 percent in 1990 to 5 percent in 2015.
More than half of the male smokers in the world lived in just three countries in 2015, the researchers found. China had approximately 254 million male smokers, India had about 91 million and Indonesia had about 50 million.
Although China, India and Indonesia had the highest numbers of male smokers, it was the Pacific island nation of Kiribati that had the highest rates of male smokers, the researchers found. Nearly 50 percent of the men in Kiribati smoked on a daily basis in 2015.
The countries with the most female smokers in 2015 were the U.S. (17 million smokers), China (14 million smokers) and India (13.5 million smokers). Together, these three countries accounted for just over one-quarter of the female smokers worldwide, the researchers found.
The highest rate of female smoking in 2015 was in Greenland: The researchers found that 44 percent of the women in the Danish territory smoked daily, according to the study.
More than 11 percent of deaths worldwide were due to smoking in 2015, according to the study, and just over half of these deaths occurred in four countries: China, India, the U.S. and Russia.
Originally published on Live Science.
Live Science newsletter
Stay up to date on the latest science news by signing up for our Essentials newsletter.