Second-hand tobacco exposure in children: evidence for action
Authors: Francois Alla
Journal: The Lancet Public Health (2021)

Tobacco is one of the leading risk factors for disease burden and death in the world. This burden is related to both tobacco consumption and second-hand exposure. Children are particularly exposed; in 2019, it was estimated that passive smoking was responsible for 50 000 deaths and 4 500 000 disability-adjusted life-years among children younger than 14 years.1GBD 2019 Risk Factors CollaboratorsGlobal burden of 87 risk factors in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019.Lancet. 2020; 396: 1223-1249Summary Full Text Full Text PDF PubMed Scopus (968) Google Scholar Over the last two decades, especially following WHO's Framework Convention on Tobacco Control in 2003, comprehensive tobacco control policies (including smoking bans) have been promoted internationally and implemented in many countries worldwide. These policies have proven to be effective in reducing smoking prevalence.2Flor LS Reitsma MB Gupta V Ng M Gakidou E The effects of tobacco control policies on global smoking prevalence.Nat Med. 2021; 27: 239-243Crossref PubMed Scopus (23) Google Scholar In addition, these policies are associated with substantial benefits for children's health.3Faber T Kumar A Mackenbach JP et al.Effect of tobacco control policies on perinatal and child health: a systematic review and meta-analysis.Lancet Public Health. 2017; 2: e420-e437Summary Full Text Full Text PDF PubMed Scopus (95) Google Scholar The burden of second-hand exposure decreased by 80% among children younger than 14 years between 1990 and 2019.1GBD 2019 Risk Factors CollaboratorsGlobal burden of 87 risk factors in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019.Lancet. 2020; 396: 1223-1249Summary Full Text Full Text PDF PubMed Scopus (968) Google Scholar In this context, the question arises of exposures that have received little or no consideration in these national strategies, which are mainly focused on indoor public spaces and workplaces. Such environments include outdoor areas (eg, parks), semi-private places (eg, community buildings), and private places (eg, cars). Numerous national and local initiatives have been implemented to reduce these exposures;4Martínez C Guydish J Robinson G Martínez-Sánchez JM Fernández E Assessment of the smoke-free outdoor regulation in the WHO European Region.Prev Med. 2014; 64: 37-40Crossref PubMed Scopus (18) Google Scholar however, they are still substantial.5Jeong SH Jang BN Kang SH Joo JH Park EC Association between parents' smoking status and tobacco exposure in school-age children: assessment using major urine biomarkers.Sci Rep. 2021; 114536Google Scholar, 6Henderson E Continente X Fernández E et al.Secondhand smoke exposure and other signs of tobacco consumption at outdoor entrances of primary schools in 11 European countries.Sci Total Environ. 2020; 743140743Crossref PubMed Scopus (6) Google Scholar Data on their effectiveness are needed to support their implementation. Evaluating the effects of these strategies on children's health is the focus of the systematic review and meta-analysis by Márta Radó and colleagues in The Lancet Public Health.7Radó MK Mölenberg FJM Westenberg LEH et al.Effect of smoke-free policies in outdoor areas and private places on children's tobacco smoke exposure and respiratory health: a systematic review and meta-analysis.Lancet Public Health. 2021; (published online July 15.)https://doi.org/10.1016/S2468-2667(21)00097-9Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar This research is particularly important because these measures can be challenging to implement, given that they rely on individual and collective behaviours, and that their social acceptability can be low.8Boderie NW Mölenberg FJ Sheikh A et al.Assessing public support for extending smoke-free policies beyond enclosed public places and workplaces: protocol for a systematic review and meta-analysis.BMJ Open. 2021; 11e040167Crossref PubMed Scopus (4) Google Scholar This study is even more relevant currently as the COVID-19 pandemic and associated safety measures have probably led to an increase in tobacco consumption and domestic exposure.9Alla F Berlin I Nguyen-Thanh V et al.Tobacco and COVID-19: a crisis within a crisis?.Can J Public Health. 2020; 111: 995-999Crossref PubMed Scopus (18) Google Scholar Additionally, children have been among the main collateral victims of the crisis.10Phumaphi J Mason E Alipui NK et al.A crisis of accountability for women's, children's, and adolescents' health.Lancet. 2020; 396: 222-224Summary Full Text Full Text PDF PubMed Scopus (4) Google Scholar On the basis of seven studies considered to be of sufficient quality, Radó and colleagues showed that smoke-free policies were associated with a reduction in tobacco smoke exposure in cars (n=5 studies) and on school grounds (n=1), and that a comprehensive smoke-free policy was associated with a decrease in child hospital attendance for respiratory tract infections (n=1). These results are important and emphasise the value of such measures. Communities and states should be encouraged to continue their efforts to reduce children's exposure to tobacco smoke. Nevertheless, Radó and colleagues' study also shows that the available data are scarce and of heterogeneous quality, and present a low level of evidence. Thus, a strengthening of evaluative research in this area is clearly needed. We need methodologically robust studies, such as comparative, quasi-experimental, or even experimental studies with valid measures of exposure and health outcomes. Furthermore, from a public health perspective, it is crucial to have a global measure of total exposure to tobacco smoke across all environments rather than specific measures (eg, in cars). It cannot be ruled out that there could be some adverse effects of such policies; for example, the displacement of smoking from public to private places, such as inside the home, which would be harmful to children.11Faber T Mizani MA Sheikh A Mackenbach JP Reiss IK Been JV Investigating the effect of England's smoke-free private vehicle regulation on changes in tobacco smoke exposure and respiratory disease in children: a quasi-experimental study.Lancet Public Health. 2019; 4: e607-e617Summary Full Text Full Text PDF PubMed Scopus (13) Google Scholar To date, there is scarce and conflicting evidence on this topic. Results from well conducted studies would be useful to implement smoke-free policies, to improve the social acceptability of these measures, and to support changes in collective and individual behaviour. I declare no competing interests. Effect of smoke-free policies in outdoor areas and private places on children's tobacco smoke exposure and respiratory health: a systematic review and meta-analysisSmoke-free car policies are associated with reductions in reported child TSE in cars, which could translate into respiratory health benefits. Few additional studies assessed the effect of policies regulating smoking in outdoor areas and semi-private and private places on children's TSE or health outcomes. On the basis of these findings, governments should consider including private cars in comprehensive smoke-free policies to protect child health. Full-Text PDF Open Access