April 6 (UPI) -- Research finds smoking causes 1 in 10 deaths worldwide, with half of those deaths in the United States, Russia, China and India.
The Global Burden of Diseases, Injuries, and Risk Factors Study, based on information on smoking in 195 countries and territories from 1990 to 2015, found that roughly 1 billion people smoked in 2015 -- 1 in 4 men and 1 in 20 women.
Researchers found a staggering number of smokers despite the known negative health effects of smoking and its cancer-causing properties and worldwide anti-smoking campaigns.
The study showed a significant reduction in smoking prevalence from 1990 to 2005 and 2005 to 2015 in 13 countries, including the United States, Australia and Brazil, and 18 countries also showed a decline in prevalence in the number of people who smoke every day.
According to the Centers for Disease Control and Prevention, 15 of every 100 U.S. adults age 18 and older smoke cigarettes.
In 2015, 11.5 percent of deaths worldwide were attributed to smoking and 52.2 percent of those deaths occurred in the United States, Russia, China and India.
From 1990 to 2015, the prevalence of smoking decreased worldwide by 29.4 percent to 15.3 percent in 2015. There were more than 6.4 million smoking-related deaths in 2015, an increase of 4.7 percent.
Smoking was ranked among the five leading risk factors for disability-adjusted life-years in 109 countries and territories in 2015, an increase from 88 countries in 1990.
Population growth is partly responsible for the overall number of smokers increasing from 870.4 million in 1990 to 933.1 million in 2015.
"Despite more than half a century of unequivocal evidence of the harmful effects of tobacco on health, today, 1 in every 4 men in the world is a daily smoker," Dr. Emmanuela Gakidou, study author, said in a press release. "Smoking remains the second-largest risk factor for early death and disability, and so to further reduce its impact we must intensify tobacco control to further reduce smoking prevalence and attributable burden."
The study was published in The Lancet.