Diabetes and periodontal disease: a 4-year prospective cohort study

Objectives: Periodontitis is often associated with impaired glucose tolerance; however, there are few reports of cohort studies in a general population. To prospectively examine the association of periodontal disease with diabetes, we analyzed data from a worksite cohort study in Japan. Obesity has been found to contribute significantly to diabetes, and obesity and periodontal disease are also correlated. As part of the study, the simultaneous exposure to both factors was also assessed. Methods: At baseline, we excluded subjects with a history of diabetes and those who had a fasting glucose level > or = 126 mg/dL. A total of 2,458 civil servants aged 40-49 years were included in the study. Subjects were divided into three categories: no pathological pocket, moderate periodontitis, and severe periodontitis, based on the Community Periodontal Index. Diabetes was defined as a fasting glucose concentration > or = 126 mg/dL at least once during the follow-up period. Multivariate logistic regression analyses were performed to estimate the relative risk (RR) and 95% confidence interval (95% CI) of periodontal disease on the cumulative incidence of diabetes. Age, sex, smoking, body mass index, g-GTP, and hypertension were adjusted in the multivariate analysis. Results: During a 4-year follow-up period, 87 subjects were diagnosed with diabetes. Subjects with severe periodontitis were found to have a higher risk of incidence of diabetes, but moderate periodontitis was not associated with increased risk: RR was 2.02 (95%CI: 1.09-3.77) and 0.97 (95%CI: 0.60-1.59), respectively. Simultaneous exposure to both severe periodontitis and obesity was associated with a remarkably elevated risk for the incidence of diabetes (RR=3.93, 95%CI: 1.65-9.38). Conclusion: Periodontal disease is a potential risk factor for diabetes in middle-aged adults. Acknowledgements: A part of this study was supported by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS.KAKENHI) (No.19592421).