Date of Award


Document Type

Campus Access Dissertation


Epidemiology and Biostatistics



First Advisor

Anwar T Merchant


BACKGROUND AND OBJECTIVES: Adult periodontitis is commonly considered as a chronic inflammatory disease resulting from low-grade oral infection associated with type 2 diabetes mellitus (T2DM). However, its relation including metabolic syndrome and the understanding of biological pathways are under-studied. This study aimed to investigate the relationship between periodontitis and impaired fasting glucose (IFG), and diabetes, and the other metabolic syndrome components and to study the roles of C-reactive protein (CRP) and periodontal pathogens (Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis).

RESEARCH DESIGN AND METHODS : Participants in the National Health and Nutrition Examination Survey III aged 20 years and older who received periodontal examinations and provided blood samples (n = 12,254) were grouped into quintiles of mean clinical attachment loss (CAL) and pocket depth (PD), with the lowest category being the reference. The information of IgG antibodies was obtained from 5,731 participants. Plasma fasting glucose was categorized into three groups (normal < 100 mg/dL; IFG ¡Ý 100 but < 126 mg/dL; and diabetic ¡Ý 126 mg/dL). Central obesity was defined as elevated waist circumference (¡Ý 40 inches in men and ¡Ý 35 inches in women). Sociodemographic and other potential risk factors were obtained.

RESULTS: Participants in top quintile of CAL had higher prevalence odds of IFG (odds ratio [OR] 1.55 [95% CI 1.16¨C2.07]) and diabetes (4.77 [2.69¨C8.46]) after adjustment for related confounders, compared with the reference. Correspondingly, the ORs in PD were 1.39 [1.00¨C1.92] in IFG and 1.63 [1.10¨C2.42] in diabetes. ORs for CAL and PD tended to increase from the lowest to the highest with significant trend. Stronger associations between PD and diabetes existed in elevated CRP and higher P. gingivalis with significant interaction. There were much stronger relations between periodontitis and IFG and diabetes (ORs in highest CAL, 1.64 and 17.82, respectively) among individuals with no central adiposity compared to central obese people.

CONCLUSIONS: Chronic periodontitis was positively associated in a linear relation with IFG and diabetes. Combining information from clinical measurements and microbial biomarkers of periodontitis and CRP may improve T2DM prediction. Individuals without central adiposity having periodontitis are more likely to have hyperglycemia than those without.