Some 2.7 billion people are exposed to secondhand smoke worldwide, the prevalence of which is increasing in Africa and the Middle East, and which is estimated to have caused 1.66 million deaths in 2023, according to a study published Tuesday, September 8 in The Lancet.
If " Exposure to secondhand smoke is a globally recognized health risk, for which there is no safe inhalation threshold.«" , LThe authors reviewed all the studies published on the PubMed website. – an online library of medical scientific studies, managed by the US National Institutes of Health – from 2010 to 2025, to try to assess its impact on nine health consequences, including asthma.
Data from 204 countries analyzed over more than three decades
Their work, by synthesizing general population surveys and household composition data, seeks to estimate the prevalence of exposure to passive smoking and to quantify the burden of disease attributable to it in 204 countries and territories between 1990 and 2023, by age and sex.
They calculated that approximately 2.7 billion people worldwide were exposed to secondhand smoke that year, including 767 million children aged 0 to 14.
This exposure would have resulted in 1.66 million premature deaths, out of the 8 million deaths attributable to tobacco in 2023.
Passive smoking is also estimated to have caused the loss of 44.8 million years of healthy life worldwide, primarily due to ischemic heart disease, a heart condition caused by a lack of oxygen in the heart muscle, according to this study.
In children, exposure to secondhand smoke is estimated to have caused 5.16 million respiratory infections, also in 2023.
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The smoke that escapes from a cigarette is more toxic than the smoke that is exhaled.
Passive smokers are exposed to two types of smoke: that emanating from the burning end of tobacco products, and that exhaled by smokers. The first, "« neither filtered nor produced by complete combustion«", presents "« higher concentrations of toxic and carcinogenic compounds »"than the second.".
These exhibitions« increase the risk of cardiovascular, respiratory, and metabolic diseases«", the study reminds us, and the children"« are particularly vulnerable“.
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However, despite a 221% decrease in the global prevalence of smoking since 1990,« The absolute number of people exposed (to passive smoking) has remained stable globally, while increasing sharply in sub-Saharan Africa, North Africa, and the Middle East.«", the scientists observed.
According to the study, there is an urgent need to strengthen anti-smoking policies., «"in particular to protect women and children"«" , In "« public places as well as the domestic setting«", because passive smoking"« remains a major factor in health loss worldwide. »
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