Second-hand smoke causes nearly 1.7 million deaths globally: study

More than 2.7 billion people, including children, were exposed to second-hand smoke globally, contributing to nearly 1.7 million deaths in 2023.

That is according to a study published Tuesday in The Lancet, which found tobacco remains a leading cause of disease worldwide.

How many deaths does second-hand smoke cause?

Second-hand smoke exposure resulted in an estimated 1.66 million premature deaths in 2023, alongside widespread disability and illness. Ischemic heart disease, a condition caused by insufficient oxygen supply to the heart muscle, was the leading cause. These deaths formed part of a broader estimated total of 8 million people who died that year of smoking-related illnesses.

How many people are exposed to second-hand smoke worldwide?

Around 2.7 billion people were exposed to second-hand smoke globally in 2023, according to the study. This figure included 767 million children aged 0 to 14. The study reviewed research published in the US National Institutes of Health database PubMed, along with population surveys, to estimate exposure and disease burden across 204 countries and territories between 1990 and 2023.

How does second-hand smoke affect children?

Exposure to second-hand smoke is estimated to have caused 5.2 million respiratory tract infections in children in 2023. People near someone smoking are exposed to both sidestream smoke from the burning tobacco and smoke exhaled by the active smoker, the study explained. It said the sidestream component dominates the air non-smokers breathe and is unfiltered, carrying higher concentrations of toxic and carcinogenic compounds than what the smoker inhales directly.

Why has second-hand smoke exposure stayed high despite falling smoking rates?

Global smoking prevalence has declined significantly since 1990, yet the absolute number of people exposed to second-hand smoke has remained stable. Population growth and rising exposure in Africa and the Middle East have offset the drop in smoking rates. The study also found that women are disproportionately affected, particularly in regions where female smoking rates are low, and said this burden is rarely acknowledged as a major risk factor for female health.

The study called on governments to strengthen tobacco controls in public places and in homes. It said doing so would better protect women and children from the health risks of second-hand smoke, which it described as carrying no safe level of inhalation.