Periodontitis and pre-diabetes

Background + Aims

• Pre-diabetes is a condition where blood glucose levels are higher than normal but not yet high enough for a diabetes diagnosis.
• Impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) are independent markers of increased risk for type 2 diabetes and cardiovascular disease.
• Periodontitis is characterised by inflammation, tissue damage, and increased systemic inflammatory markers. Chronic periodontal infection is suggested to contribute to impaired glucose regulation.
• While previous studies have highlighted a link between periodontitis and diabetes, this research uniquely compares the relationships of periodontitis with IFG and IGT, considering the differences in their pathophysiology and risk profiles.
• The study aims to investigate whether clinical measures of periodontitis assessed via full-mouth examinations, are associated with IFG and IGT among adults in the US using data from the Continuous National Health and Nutrition Examination Survey (NHANES) 2009–2010.

Materials + Methods

• This cross-sectional analysis used data from NHANES 2009–2010, a nationally representative study.
• Participants included adults aged 30–80 years without diabetes.
• Exclusions included self-reported diabetes diagnosis, glycated haemoglobin (HbA1c) ≥6.5%, fasting glucose ≥126 mg/dL, or inadequate fasting during the oral glucose tolerance test (OGTT).
• The final sample consisted of 1,165 individuals.
• Periodontal assessments were undertaken by trained hygienists conducting full-mouth periodontal examinations. They measured probing pocket depth (PPD) and clinical attachment loss (CAL) at 6 sites per tooth.
• Periodontitis was categorised as none/mild, moderate, or severe using the CDC/AAP definition.
• Participants underwent an OGTT to measure fasting and 2-hour post-challenge glucose levels. IFG was defined as fasting glucose 100–125 mg/dL, while IGT was defined as 2-hour glucose 140–199 mg/dL.
• Statistical analysis involving logistic regression models assessed the odds of IFG and IGT across periodontal status categories, adjusting for demographic factors, behaviours (e.g., smoking, physical activity), and clinical factors like BMI and inflammation markers.
• Directed acyclic graphs (DAGs) guided confounder selection.

Results

• Severe periodontitis was associated with a 93% increase in the odds of IGT (OR 1.93; 95% CI: 1.18–3.17), while associations with IFG were weak and not statistically significant.
• Participants with PPD or CAL in the top 25th percentile had double the odds of IGT compared to those below the 75th percentile (OR 2.05; p = 0.005).
• Periodontitis was not strongly associated with IFG, suggesting a more specific link with IGT.
• Higher levels of inflammatory markers (e.g., CRP) were observed in participants with IGT, supporting the role of systemic inflammation in impaired glucose regulation.
• Age, smoking, and BMI were significant confounders, but their adjustment did not diminish the observed association.

Limitations