A new global study highlights that children remain disproportionately affected by second-hand smoke (SHS), suffering from respiratory illnesses, growth issues, and long-term disease risks. Published in the peer-reviewed journal Respiratory Research (2025), the analysis underscores the urgent need for stronger protective measures.
Though children are non-smokers, repeated exposure, whether at home, in public areas, or indoors with smokers—remains a major contributor to childhood disease burden, causing numerous deaths and disabilities worldwide.
Global Burden of Disease Findings
The Global Burden of Disease 2021 analysis shows that while age-standardized exposure levels to SHS have modestly declined since 1990, the absolute number of deaths and disability-adjusted life years (DALYs) attributable to SHS has not decreased, largely due to population growth and ageing. Around 50% of children globally are still exposed to second-hand smoke.
Low- and middle-income countries, particularly those with lower socio-demographic indices (SDI), bear the greatest burden, partly due to weaker enforcement of smoke-free indoor air policies. In 2019, an estimated 6.94% of deaths from lower respiratory infections (LRIs) among children under five were linked to SHS, with infants under one year being especially vulnerable.
Health Impacts on Children
Exposure to SHS increases the risk of chronic respiratory diseases, asthma exacerbations, ear infections, and reduced lung function later in childhood. Molecular studies suggest that SHS may also alter DNA methylation in children, potentially increasing susceptibility to future diseases.
Second-hand smoke is particularly harmful when exposure occurs at home. While public bans often protect children in outdoor or communal areas, many remain exposed indoors, in private homes or cars, by caregivers or family members. Social, economic, and cultural factors—such as crowded living conditions, poor ventilation, lower awareness, and limited regulatory enforcement—further elevate risks in lower SDI regions.
WHO data also link SHS to stunting, affecting nearly 150 million children worldwide in 2022. Both maternal smoking and postnatal SHS exposure contribute to low height-for-age in children.
Recommended Measures
Experts recommend a combination of policy, awareness, and practical measures to reduce SHS exposure among children:
Second-hand smoke is not a distant or minor threat. It remains a pervasive contributor to illness, impaired growth, and death among children worldwide. While exposure has declined in some regions, population growth, ageing, and inconsistent policies mean millions of children continue to suffer. Protecting them requires coordinated action from governments, health authorities, caregivers, and communities, along with practical steps in daily life.