Is secondhand smoke exposure associated with poor periodontal status in children and adolescents? A systematic review and meta-analysis

Purpose We aimed to systematically evaluate whether SHS exposure is associated with poor periodontal status in individuals up to 15 years. Methods Seven databases were searched by two independent reviewers according to pre-specified eligibility criteria up to November 2021. The methodological quality of included studies was appraised using The Newcastle–Ottawa Scale and GRADE was used for assessing the certainty of evidence. Random-effects pairwise meta-analyses compared the periodontal status of those exposed and unexposed to SHS through standardized mean differences (SMDs) and associated confidence intervals (95% CI). Results Eight cross-sectional studies were eligible for inclusion and two present high methodological quality. All studies contributed to the meta-analysis for gingival index scores (GI) and four for probing pocket depth (PPD). Those exposed exhibited significantly higher levels of GI compared to unexposed (SMD = 1.03, 95% CI 0.17–1.89), but no difference was observed for PPD (SMD = 0.34, 95% CI − 0.14–0.82), with overall very low certainty on evidence. Conclusion Therefore, very low certainty evidence supports that children and adolescents exposed to SHS possibly present poorer periodontal status due to higher levels of GI.