Secondhand smoke is still a deadly global threat. A landmark Global Burden of Disease study published in Lancet Public Health found that an estimated 2.71 billion people were exposed to secondhand smoke in 2023 — resulting in 1.66 million deaths and 44.8 million disability-adjusted life years (DALYs) lost. This is the first GBD study to evaluate secondhand smoke as an independent global risk factor, covering 204 countries from 1990 to 2023.

Women and children bore a disproportionate share of the burden. Nearly 1.49 billion of those exposed were women, and 767 million were children aged 0–14. In some countries, women faced 1.8 times greater exposure than men. Ischemic heart disease was the top driver of DALYs in adults, while lower respiratory infections led among youth.

By the Numbers:

• 2.71 billion people exposed to secondhand smoke globally in 2023
• 1.66 million deaths attributed to secondhand smoke exposure
• 44.8 million DALYs lost; 39.1 million years of life lost
• Age-standardized exposure dropped 22.2% since 1990 — but population growth kept absolute numbers stable
• 24 of 79 top-performing countries for smoke-free protections are in the Americas

Why it matters: Despite progress in tobacco control policies, population growth is offsetting hard-won gains. Experts are calling for broader measures — including taxation, marketing bans, and cessation programs — and urging clinicians to routinely screen women, children, and patients with cardiac or lung conditions for secondhand smoke exposure.