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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
National smoke-free legislation in advanced economies is linked to reduced rates of preterm birth, asthma hospitalisations and serious throat and chest infections in children. Comprehensive smoke-free policies appear to be more effective than policies with only partial or selective introduction.
Smoking increases health risks for the smoker and others through second-hand exposure. Although the number of people smoking in the UK is falling, eight million UK adults still smoke, and an estimated five million children are exposed to second-hand smoke. Children are vulnerable to smoke due to their small, developing lungs and immune systems.
Evaluations of tobacco control policies have often looked at adult outcomes; predominantly change in smoking rates. This review looked for evidence of the impact of these policies on children.
These findings underline the importance of continuing efforts at a systems level to reduce smoking and improve children’s health.
Why was this study needed?
Nearly 16% of the adult population in the UK continue to smoke. Smoking has well-established health risks for smokers and those around them, including increased risk of cancer and cardiovascular conditions. Smoking or regular smoke exposure in pregnancy increases the risk of miscarriage, preterm birth and babies born small for their age. There are also links with stillbirth and sudden infant death syndrome. Worldwide about 40–50% of children are regularly exposed to second-hand smoke.
The World Health Organization created a Framework Convention on Tobacco Control to support countries in creating policies and laws to reduce smoking rates to improve people’s health. This centred upon six “MPOWER” measures: monitoring tobacco use, creating smoke-free environments, supporting people to quit smoking, raising awareness about the dangers of smoking and second-hand smoke, banning tobacco advertising and taxing tobacco products.
This review looked at the impact of implementing tobacco control measures, with a unique focus on second-hand smoke and children’s health.
What did this study do?
This systematic review included 41 studies that assessed the association between any MPOWER policies and infant or child health outcomes. These policies are explained in the Definitions tab. The acronym originates from the WHO and includes the measures that governments can take to reduce smoking. The majority (35) of studies in this review were related to legislation for smoke-free public spaces; the others looked at taxation (11) and smoking cessation services (3).
Studies were from North America (24) and Europe (16) with one study from Hong Kong. Studies were included if most of the study population were younger than 12 years old.
Nearly all studies used an interrupted time series design, which uses measurements taken regularly over time (the “time series”) that are “interrupted” by the introduction of a new policy or intervention. These studies are particularly suited to evaluating the effect of broad policy interventions at a population level.
The included studies were mainly judged as at low-to-moderate risk of bias, though there was a possibility that studies with positive findings were more likely to be published and not all system level changes were the same.
What did it find?
- Following the introduction of policies banning smoking in public places, rates of preterm birth decreased by 3.77% (95% confidence interval [CI] ‑6.37 to ‑1.16; ten studies, 27,530,183 people).
- Asthma flare-ups requiring a hospital visit reduced by 9.83% (95% CI ‑16.62 to ‑3.04; five studies, 684,826 events).
- Smoke-free legislation was also associated with a 3.45% reduction in the number of child hospital admissions for nose, throat or chest infections (‑3.45%, 95% CI ‑4.64 to ‑2.25; two studies, 1,681,020 events). There was a greater effect in studies looking at chest infections, specifically (-18.48%, 95% CI -32.79 to -4.17; three studies, 887,414 events).
- Only two studies looked at effects on stillbirths or infant deaths, and the results were inconsistent and could not be pooled in a meta-analysis.
What does current guidance say on this issue?
In England and Wales, 2007 legislation made it illegal to smoke in enclosed workplaces and public places (such as pubs), then 2015 legislation banned smoking in a vehicle when children are present.
NICE‘s 2010 guidelines recommend that all health professionals identify pregnant women or others in their household who smoke so that they can be referred to NHS Stop Smoking Services. This service includes talking therapies such as cognitive behavioural therapy and motivational interviewing.
What are the implications?
This review demonstrates that national smoke-free legislation may have a positive influence on infant and child health. The temporal link with the policy introduction does support other evidence that the national level action has been part of the explanation for falling rates of smoke-related diseases in children.
The evidence is consistent with findings from other studies but is limited to some extent by relatively few child health outcomes that could be assessed at this scale, and the lack of studies investigating other policies such as tobacco taxation separately.
It is important to continue to evaluate these policies to promote awareness of the importance and success of system-level interventions for tobacco control and smoking cessation.
Citation and Funding
Faber 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(9):e420-37.
This project was funded by the Chief Scientist Office Scotland, Farr Institute, Netherlands Lung Foundation, Erasmus MC.
Bibliography
NICE. Smoking: stopping in pregnancy and after childbirth. PH26. London: National Institute for Health and Care Excellence; 2010.
Office for National Statistics. Adult smoking habits in the UK: 2016. Newport: Office for National Statistics; 2017.
Smokefree NHS. Protect your family from secondhand smoke. London: Public health England.
Smokefree NHS. Stopping smoking is the best thing you can do for your baby. London: Public health England.
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