Second-hand smoke associated with 1.66 million premature deaths in 2023, study finds

More than 2.7 billion people worldwide were estimated to have been exposed to second-hand smoke in 2023, including 767 million children aged 0 to 14, according to a study published in The Lancet.

The study estimated that exposure was associated with 1.66 million premature deaths and millions of cases of illness. Ischaemic heart disease was the leading contributor to the related premature deaths and disease burden.

Among children, second-hand smoke exposure was estimated to have been associated with 5.2 million respiratory tract infections in 2023. The study said there was no safe level of exposure.

Researchers reviewed studies in the US National Institutes of Health’s PubMed database and population surveys to assess exposure and related disease across 204 countries and territories between 1990 and 2023. The figures are modelled estimates rather than direct counts.

Although smoking prevalence has declined globally since 1990, the absolute number of people exposed to second-hand smoke has remained stable, partly because of population growth and increased exposure in Africa and the Middle East. Women were disproportionately affected in regions where smoking among women is uncommon.

The study called on governments to strengthen tobacco controls in public places and homes, with a particular focus on protecting women and children. Second-hand smoke includes smoke from burning tobacco products and smoke exhaled by smokers.