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UPI.com

Secondhand smoke still kills -- just not as much as it used to.

That's the finding of an analysis published Tuesday by JAMA Network Open. The researchers estimated that more than 880,000 people worldwide died from exposure to secondhand smoke in 2016, compared to nearly 950,000 in 1990.

This despite the fact that there were more smokers globally in 2016 -- nearly one billion, thanks in large part to increasing popularity of the habit in Asia and Africa -- than in 1990, when roughly 850 million people smoked worldwide.

The figures suggest that one non-smoker died from exposure to secondhand smoke for every 52.3 smokers in 2016, a significant change from the ratio of one for every 31.3 smokers in 1990.

"We calculated the harm inflicted by an individual smoker to a non-smoker," study co-author Leonard Hofstra, a cardiologist at the Cardiology Centers of the Netherlands, told UPI. "Our study demonstrates that around 50-lifetime smokers are responsible for the death of one smoker. This means that a smoker is not only a victim of the addiction to nicotine, but also an offender, who does harm to others."

Indeed, the stats indicate that, in general, there is less secondhand smoke in the air we breathe in most parts of the world, and that it takes more smokers to create the same amount of secondhand smoke seen 30 years ago. However, it also highlights the dangers associated with secondhand smoke.

To derive their estimates, Hofstra and his colleagues used data from the Our World in Data database to calculate the number of people who smoke in each country and number of premature deaths related to secondhand smoke in each country between 1990 and 2016. The mean number of cigarettes smoked in all countries was also included in the analysis.

The authors also collected smoking data for each of the World Bank regions: North America, Latin America and the Caribbean, Europe and Central Asia, the Middle East and North Africa, sub-Saharan Africa, South Asia and East Asia and the Pacific.

In addition to the global figures for death of non-smokers exposed to secondhand smoke, the authors found that, in 2016, several regions still had above-average rates of smoker-caused mortality. For example, in the Middle East and North Africa, where smoking remains more common, one non-smoker died from exposure to secondhand smoke for every 42.6 smokers.

Conversely, in North America, this figure is one for every 85.7.

The authors also noted that there was substantial reduction in the number of children younger than 5 who died from secondhand smoke exposure, from 272,176 in 1990, which was 28.8 percent of all secondhand smoke-related deaths, to 53,566 in 2016, or 6.1 percent of deaths. As vaping "is still quite new and low in volume compared to cigarette smoking, the impact (on) second-hand smoke exposure and subsequent harm is unknown," Hofstra said.

"The study clearly shows that the average lifetime smoker is 2 percent responsible for the death of one non-smoker," he added. "We hope this will inspire policymakers to better protect non-smokers. We found in a survey that two-thirds of respondents found it unacceptable that smokers do any harm to non-smokers. This suggests that the general public is ready for measures to better protect non-smokers."