A systematic review of second-hand smoking mass media campaigns (2002-2022).

Background: Second-hand smoking (SHS) increases the risk of chronic disease in adults and poses a serious health threat to children. Mass media campaigns are instrumental in raising awareness and reducing SHS exposure. There is a need to identify recent SHS mass media campaigns and assess their sustainability in terms of knowledge, attitudes, and behavioural changes. This systematic review summarises the characteristics and outcomes of mass media campaigns on SHS prevention.

Methods: PubMed, Embase, Web of Science, and grey literature were searched in November 2022 for SHS campaigns implemented between 2016 and 2022. The eligibility criteria included campaigns on the dangers or effects of SHS with any target group, dissemination medium, study design, or language. The database search identified 1,413 peer-reviewed titles, of which 82 full-texts were screened, with 14 meeting the eligibility criteria. The grey literature search identified 9,807 sources, of which 61 were included. We extracted data on the campaign characteristics, metrics, and smoking-related outcomes. The JBI critical appraisal tool was used to assess the risk of bias of the included studies.

Results: We found 73 SHS campaigns conducted between 2002 and 2022, across 50 countries. The campaigns reached 378 million people. The reported recall rates range from 8 to 76%. Of the 11 studies that reported smoking-related outcomes, 10 reported increased knowledge in understanding SHS risks (73-85%), five reported an increased prevalence of smoke-free homes, and two reported an increase in number of participants persuading others to quit smoking. Two studies reported a decrease in overall smoking, whereas three studies observed a reduction in smoking in the presence of children.

Conclusion: The available data provide some support for the effectiveness of SHS campaigns in reducing smoking behaviours in homes and around children. However, the certainty of evidence was low due to the lack of a control group and the substantial heterogeneity in the outcomes assessed. Future campaigns need comprehensive evaluation and reporting to reduce publication bias.