Second-hand smoke exposure linked to nearly 1.7 million deaths worldwide in 2023, study finds

PARIS — Over 2.7 billion people globally, including 767 million children aged 0 to 14, were exposed to second-hand smoke in 2023, contributing to nearly 1.7 million premature deaths, according to a study published Tuesday in The Lancet. The research highlights tobacco as a leading cause of disease worldwide, with many non-smokers affected by exposure to second-hand smoke among the estimated 8 million deaths related to smoking in 2023.

The study, which reviewed data from the US National Institutes of Health’s PubMed database and population surveys, analyzed the prevalence of second-hand smoke exposure and its disease burden across 204 countries and territories from 1990 to 2023. It found that exposure to second-hand smoke caused 1.66 million premature deaths and significant disability, with ischemic heart disease—caused by insufficient oxygen supply to the heart muscle—being the leading cause of death linked to such exposure.

Children exposed to second-hand smoke suffered an estimated 5.2 million respiratory tract infections in 2023. The study explained that individuals near smokers inhale both sidestream smoke from the burning tobacco product and smoke exhaled by the smoker. Sidestream smoke, which dominates the air non-smokers breathe, is unfiltered and contains higher concentrations of toxic and carcinogenic compounds than the smoke inhaled by active smokers.

Despite a global decline in smoking prevalence since 1990, the absolute number of people exposed to second-hand smoke has remained stable. This is attributed to population growth and increased exposure in regions such as Africa and the Middle East. The study also noted that women are disproportionately affected by second-hand smoke, especially in areas where smoking rates among women are low.

The researchers emphasized that second-hand smoke exposure remains an underrecognized major risk factor for female health. They called on governments to strengthen tobacco control measures in public spaces and homes to better protect women and children from the harmful effects of second-hand smoke.

The study underscores that there is no safe level of inhalation of second-hand smoke, which continues to pose a significant global health risk. It advocates for comprehensive policies to reduce exposure, including bans on indoor smoking and public awareness campaigns.

As tobacco remains a leading cause of preventable disease and death worldwide, the findings highlight the urgent need for enhanced tobacco control efforts to address the persistent burden of second-hand smoke exposure, particularly among vulnerable populations such as women and children.