Effectiveness of Interventions to Reduce Children’s Exposure to Secondhand Smoke at Home: A Meta-Analysis

Secondhand smoke (SHS) exposure is a major public health concern due to its serious and preventable health consequences. This meta-analysis aimed to evaluate the effectiveness of interventions to reduce home SHS exposure in children aged five years and under. The review followed PRISMA 2020 guidelines, and five databases (Cochrane Library, CINAHL Complete, PubMed, Science Direct, and Web of Science) were searched from August 2014 to the end of June 2025. Three independent reviewers screened the studies, extracted data, and compared results. The methodological quality and risk of bias of the included studies were assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist and the Cochrane Risk of Bias Tool, respectively. A total of twelve studies met the inclusion criteria. SHS exposure was measured using biomarkers in eight studies, air marker in one study, and self-report in three studies. The interventions had a medium overall effect in reducing SHS exposure (p ≤ .001; Hedges’ g = -0.245; 95% CI = -0.376 to -0.114). All twelve studies were generally well designed and had low risk of bias. Although the interventions were effective, SHS exposure among children aged five years and under remains a concern. These findings suggest that while current strategies offer some protection, they are not sufficient to eliminate exposure. Future interventions should prioritize sustainability, cultural appropriateness, and family engagement to enhance long-term effectiveness. Interventions effectively reduced secondhand smoke (SHS) exposure in the home among children aged five years and under. Complete protection from SHS exposure was not achieved, even with targeted intervention efforts. Additional or alternative strategies may be required to ensure more effective protection for young children.