Backround: Meta-analysis of the impact of public smoking bans on children's exposure to secondhand smoke (SHS) exposure at home.
Methods: The electronic databases of PubMed, Web of Science, PsycINFo, ASSIA, CINAHL were searched. German public health journals not captured by these databases and grey literature were considered in addition. Studies were included when they reported children's SHS exposure at home in relation to smoke-free legislation by measuring exposure before and after the introduction of a public smoking ban. Studies had to provide results on exposure prevalences of children aged below 18 years. Language of publications was restricted to German and English. Details of the included studies (n = 15) were extracted by one author and checked for accuracy by a second author. Given the exposure prevalences before and after the introduction of a smoke-free legislation, a random-effects meta-analysis of relative risks (RR) was conducted. Results were presented in a forest plot.
Results: Meta-analysis showed that the overall effect was a decreased exposure to SHS in the children's homes after introduction of a public smoking ban (RR = 0.72; 95% CI = 0.62-0.83). Only two of the 15 studies indicated an increased exposure. Sensitivity analyses considering the type of smoke-free legislation, children's age group and study quality did not substantially alter the result.
Conclusion: The assumption of a displacement of smoking into homes with children due to smoke-free legislation in public places could not be confirmed. Additional research is needed to analyse long-term trends.
Keywords: Displacement; Meta-analysis; Public smoking ban; Secondhand smoke exposure; Smoke-free legislation; Tobacco control.