Association Between Periodontitis and Respiratory Diseases: A Systematic Umbrella Meta-Analysis.

AIM: This study aimed to evaluate the association between periodontitis and respiratory diseases using an umbrella meta-analysis. METHODS: Meta-analyses (MAs) reporting odds ratios (OR) and mean differences (MD) for the association between periodontitis and respiratory diseases of COVID-19, chronic obstructive pulmonary disease (COPD), asthma, and pneumonia were included. Random-effects meta-analysis was performed. Egger's test and trim-and-fill method were used to assess publication bias. RESULTS: Fourteen MAs encompassing more than 500,000 participants were included. A significant association was found between periodontitis and respiratory disease (OR 2.45, 95% CI 2.06-2.92, p < 0.0001), with substantial heterogeneity (I2 = 82%). The pooled OR for the association between periodontitis with COVID-19, COPD, asthma, and pneumonia was 2.75, 1.42, 3.42, and 2.73, respectively. The association remained consistent even after adjustment for publication bias and among different study qualities and sample sizes. Notably, the association with COPD may not be independent of smoking. The GRADE assessment rated the certainty of evidence of the outcomes as "low" due to high heterogeneity and publication bias. CONCLUSIONS: The results suggest a statistical association between periodontitis and most of the studied respiratory diseases. However, these results should be interpreted with caution and be seen as exploratory and hypothesis-generating, rather than definitive effect sizes. PROSPERO REGISTRATION: CRD420251250830.