Periodontitis severity relationship with metabolic syndrome: A systematic review with meta-analysis

The objective of this study was to investigate the association between periodontitis severity and metabolic syndrome (MetS) through systematic review, registered in PROSPERO: CRD42021232120. Selected articles were independently chosen by three reviewers from six databases, including using article reference lists, up until March 2022. Eligible studies were observational, without language limitation, and in subjects aged at least 18 years. The methodological quality of selected studies was assessed using the Newcastle-Ottawa Scale. Random effects models calculated summary measurements (odds ratio-OR, 95% confidence interval, 95%CI). The I² test evaluated the statistical heterogeneity of the data. Sensitivity, subgroup, and meta-regression analyses were performed. For the reliability of evidence, the Grading of Recommendations, Assessment, Development, and Evaluations tool was used. A total of 2133 records were identified, and 14 studies were included comprising 24,567 participants. The summary odds ratio showed a positive association between individuals with moderate (OR_adjusted  = 1.26; 95%CI = 2.10-5.37; I²  = 45.85%), and severe periodontitis (OR_adjusted  = 1.50; 95%CI:1.28-1.71; I²  = 56.46%), and MetS. Subgroup and meta-regression analyses showed that study effect size was influenced by year of publication, study design, and MetS diagnostic criteria, contributing to inter-study variability. The findings showed that moderate and severe levels of periodontitis are associated with MetS, suggesting a possible dose-response effect.