Effect of periodontal disease on diabetes: systematic review of epidemiologic observational evidence

Background Periodontal disease and diabetes mellitus are common, chronic diseases worldwide. Epidemiologic and biologic evidence suggest periodontal disease may affect diabetes. Objective To systematically review non-experimental, epidemiologic evidence for effects of periodontal disease on diabetes control, complications and incidence. Data sources Electronic bibliographic databases, supplemented by hand searches of recent and future issues of relevant journals. Study eligibility criteria and participants Longitudinal and cross-sectional epidemiologic, non-interventional studies that permit determination of directionality of observed effects were included. Study appraisal and synthesis methods Four reviewers evaluated pair-wise each study. Review findings regarding study results and quality were summarized in tables by topic, using the PRISMA Statement for reporting and the Newcastle-Ottawa System for quality assessment, respectively. From 2246 citations identified and available abstracts screened, 114 full-text reports were assessed and 17 included in the review. Results A small body of evidence supports significant, adverse effects of periodontal disease on glycaemic control, diabetes complications, and development of type 2 (and possibly gestational) diabetes. Limitations There were only a limited number of eligible studies, several of which included small sample sizes. Exposure and outcome parameters varied, and the generalizability of their results was limited. Conclusions and implications of key findings Current evidence suggests that periodontal disease adversely affects diabetes outcomes, and that further longitudinal studies are warranted.