ObjectivesTo systematically reviewing the epidemiologic relationship between periodontitis (PD) and type 2 diabetes mellitus (T2DM). Materials and MethodsFour electronic databases were searched up to December, 2018. Manual search including the reference lists of included studies and relevant journals. Observational studies evaluating the relationship between T2DM and PD were included. Meta-analyses were applied using STATA. ResultsA total of 53 observational studies were included. Pooled results of cross-sectional studies found the strength of association between these two diseases was very strong (OR=3.27, p=0.000). Adjusted T2DM prevalence was significantly higher in PD patients (OR=4.04, p=0.000) and vice versa (OR=1.58, p=0.000). T2DM patients had significantly worse periodontal status, reflected in a 0.61mm deeper periodontal pocket, a 0.89mm higher attachment loss and about 2 more lost teeth (all p=0.000). Results of cohort studies found T2DM could elevate 27% risk of developing PD (p=0.000).Glycemic control state of T2DM might result in different PD outcomes. Severe PD increased 53% of incident T2DM (p=0.000) and this result was stable. In contrast, the impact of mild PD on T2DM incidence (RR=1.28, p=0.007) was less robust. ConclusionsThere is an evident bidirectional relationship between T2DM and periodontitis. Further well-designed cohort studies are needed to confirm this. Clinical RelevanceBoth dentists and physicians need to be aware of this strong connection between PD and T2DM.Control these two diseases might benefit the prevention of the incidence of each other.

Objectives: To systematically review the epidemiologic relationship between periodontitis and type 2 diabetes mellitus (T2DM).Materials and Methods: Four electronic databases were searched up until December 2018. The manual search included the reference lists of the included studies and relevant journals. Observational studies evaluating the relationship between T2DM and periodontitis were included. Meta-analyses were conducted using STATA.Results: A total of 53 observational studies were included. The Adjusted T2DM prevalence was significantly higher in periodontitis patients (OR=4.04, p=0.000), and vice versa (OR=1.58, p=0.000). T2DM patients had significantly worse periodontal status, as reflected in a 0.61 mm deeper periodontal pocket, a 0.89 mm higher attachment loss and approximately 2 more lost teeth (all p=0.000), than those without T2DM. The results of the cohort studies found that T2DM could elevate the risk of developing periodontitis by 34% (p=0.002). The glycemic control of T2DM patients might result in different periodontitis outcomes. Severe periodontitis increased the incidence of T2DM by 53% (p=0.000), and this result was stable. In contrast, the impact of mild periodontitis on T2DM incidence (RR=1.28, p=0.007) was less robust.Conclusions: There is an evident bidirectional relationship between T2DM and periodontitis. Further well-designed cohort studies are needed to confirm this finding.Clinical Relevance: Both dentists and physicians need to be aware of the strong connection between periodontitis and T2DM. Controlling these two diseases might help prevent each other’s incidence.