As periodontitis may contribute to the pathogenesis of diabetes, the effects of periodontitis on diabetes incidence and HbA1c change was quantified in a prospective cohort.

Data from an 11-year follow-up of the Study of Health in Pomerania were analyzed to evaluate the effects of periodontitis on incident diabetes and long-term HbA1c changes in 2047 subjects aged 20–81years. Diabetes was based on self-reported physician diagnoses, antidiabetic medication use, or HbA1c≥6.5% or non-fasting blood glucose levels ≥11.1mmol/L. To assess periodontal status, periodontal pockets were probed, and their depth and clinical attachment levels measured. For both measures, means and percentages of sites≥3mm were calculated. In addition, all probing depths≥4mm were summed (cumulative probing depth). Modified Poisson and multivariable linear models were applied, adjusted for age, gender, highest level of general education, marital status, waist circumference, physical activity, smoking status and follow-up time.

Over a mean follow-up period of 11.1years, 207 subjects developed diabetes. Baseline mean clinical attachment levels (CAL) and probing depths (PPD) were not significantly associated with either diabetes incidence [mean CALs, fourth quartile, incidence rate ratio=0.819, 95% confidence interval (CI): 0.489–1.370; P=0.446] or long-term changes in HbA1c (mean CAL, fourth quartile, β=−0.086, 95% CI: −0.187, −0.016; P=0.098). Sensitivity analyses using alternative exposure definitions confirmed these results.

Contrary to the currently available literature, no convincing evidence was found of any potential association between periodontitis and diabetes incidence or HbA1c change.