Association between periodontitis and diabetes

Background + Aims

• Diabetes mellitus (DM) is a chronic condition marked by high blood glucose levels due to insufficient or inefficient insulin use. Poorly managed DM increases risks of cardiovascular and kidney diseases.
• Periodontitis, a severe gum disease causing tissue and bone damage, is more prevalent in people with diabetes. Both conditions share a bidirectional relationship, where each can worsen the other.
• Evidence suggests that well-managed diabetes may reduce the risk of periodontitis. However, the connection between pre-diabetes or well-controlled diabetes and periodontitis is unclear.
• Pre-diabetes is a state where blood glucose levels are higher than normal but not high enough for a diabetes diagnosis. It affects many individuals in Western countries, yet studies exploring its link to periodontitis are inconsistent or lack proper design.
• This study aimed to examine whether pre-diabetes or well-controlled diabetes was associated with a higher prevalence of periodontitis, low tooth count or edentulism (complete loss of natural teeth) using data from the large population-based SHIP-Trend study in Germany.

Materials + Methods

• The study was part of the Study of Health in Pomerania (SHIP)-Trend, a cross-sectional survey conducted in North-Eastern Germany.
• Data were collected between 2008 and 2012 from adults aged 20–82 years. Periodontal analyses included 3,086 participants; analyses of tooth count and edentulism included 3,623.
• Periodontal health was assessed using measures like clinical attachment loss (CAL) and periodontal probing depth (PPD) through a half-mouth protocol. Tooth count and edentulism status were recorded.
• Glucose regulation categories:
  • Normal glucose tolerance (NGT).
  • Pre-diabetes: impaired fasting glucose (6.1–6.9 mmol/L), impaired glucose tolerance (two-hour glucose 7.8–11.0 mmol/L), or both, using the study’s WHO 1999 criteria.
  • Newly detected type 2 diabetes: fasting plasma glucose ≥7.0 mmol/L or two-hour glucose ≥11.1 mmol/L following a 75-g oral glucose tolerance test.
  • Known diabetes, well-managed (HbA1c <7.0%).
  • Known diabetes, poorly managed (HbA1c ≥7.0%).
• Laboratory measures included fasting plasma glucose, oral glucose tolerance tests and HbA1c. The HbA1c threshold of 7.0% classified glycaemic control in previously known diabetes; it was not the criterion used to identify newly detected diabetes.
• Statistical analysis adjusted for confounders like age, BMI, smoking, and socioeconomic factors. Regression models evaluated associations between glucose regulation and periodontal outcomes.

Results

• After adjustment for confounders, pre-diabetes was not significantly associated with the assessed periodontal measures, low tooth count or edentulism.
• Previously known diabetes with HbA1c <7.0% was not significantly associated with the assessed outcomes compared with normal glucose tolerance. For edentulism, the adjusted odds ratio (OR) was 1.40 (95% CI 0.82–2.38).
• Previously known diabetes with HbA1c ≥7.0% was associated with greater mean CAL (p = 0.02 in the model using square-root-transformed CAL) and higher odds of edentulism (adjusted OR 2.19; 95% CI 1.18–4.05).
• In this poorly controlled known-diabetes group, associations with low tooth count, the categorical periodontitis definition and probing-depth outcomes were not statistically significant after full adjustment.
• Newly detected diabetes was associated with higher odds of being in the highest quarter of mean PPD (adjusted OR 1.50; 95% CI 1.04–2.17). This finding concerned a categorised probing-depth measure; the association with continuous mean PPD was not significant after full adjustment.

Limitations

• The cross-sectional design prevents establishing causation between diabetes and periodontitis.
• Only 64 participants in the periodontal analysis had previously known diabetes with HbA1c ≥7.0%; most had HbA1c ≤8.0%. This limited the precision of estimates and the representation of more marked hyperglycaemia.
• The half-mouth examination protocol might not capture the full extent of periodontitis.
• Self-reported diabetes diagnoses, though generally valid, might introduce inaccuracies.

Conclusion

• Pre-diabetes and well-controlled known diabetes were not significantly associated with the assessed periodontal and tooth-count outcomes after adjustment. Poorly controlled known diabetes was associated with greater attachment loss and edentulism, but not every periodontal outcome.
• These cross-sectional findings describe associations at one time point. They do not establish absence of future periodontal risk in pre-diabetes or well-controlled diabetes, or demonstrate that improving glycaemic control prevents tooth loss.