Association between periodontitis and diabetes

Background + Aims

• Periodontitis and diabetes frequently occur together, but shared risk factors and the timing of disease onset complicate interpretation.
• This study examined the cross-sectional association between estimated severe periodontitis and diabetes in participants from the Spanish di@bet.es study.

Materials + Methods

• The original population-based cohort enrolled 5,072 adults in 2008–2010. This analysis included 1,751 participants without diabetes at baseline who completed an oral-health questionnaire at the 2016–2017 reassessment.
• Diabetes was defined by fasting plasma glucose ≥126 mg/dL, 2-hour glucose ≥200 mg/dL, HbA1c ≥6.5%, or glucose-lowering medication. Prediabetes criteria included fasting glucose 100–125 mg/dL, 2-hour glucose 140–199 mg/dL or HbA1c 5.7–6.4%.
• Severe periodontitis was estimated using validated algorithms combining questionnaire responses with demographic and risk factors. Full-mouth examinations in a 231-person subgroup had been used to develop and validate these algorithms; the entire cohort did not receive clinical periodontal examinations.
• Three definitions were modelled: CDC/AAP severe periodontitis, ≥50% of teeth with clinical attachment loss (CAL) ≥5 mm, and ≥25% of teeth with probing pocket depth (PPD) ≥6 mm.
• Regression analyses examined associations with glycaemic categories, with adjustment for demographic, behavioural and metabolic confounders. Because periodontal status was assessed only at follow-up, this was a cross-sectional periodontal analysis despite the earlier diabetes follow-up.

Results

• There were 144 new diabetes cases among 1,751 participants (8.2%) between baseline and reassessment.
• Algorithm-estimated severe periodontitis prevalence was 59.0% using CDC/AAP criteria, 54.7% using extensive CAL, and 68.8% using deep-pocket criteria. These are predicted classifications, not clinically measured prevalence in all participants.
• All three periodontal definitions were associated with diabetes before adjustment. After full adjustment, only the extensive-CAL definition remained statistically significant: OR 4.90 (95% CI 2.24–10.72; p < 0.001).
• This represents higher odds of diabetes at reassessment among those classified with extensive attachment loss; it does not show that baseline periodontitis increased subsequent diabetes incidence.

Limitations

• Algorithm-based periodontal classification can misclassify individuals and is not equivalent to a full-mouth examination.
• No baseline periodontal measurements were available, so the temporal sequence of periodontitis and diabetes cannot be established.
• Associations differed by periodontal definition and remained susceptible to residual confounding. Only a subset of the original cohort contributed to this analysis.

Conclusion

• Estimated extensive periodontal attachment loss was associated with diabetes in this Spanish sample. The findings support an association between the conditions but do not demonstrate causation or establish that periodontal treatment prevents diabetes.