Many studies have demonstrated an increased incidence of apical periodontitis in patients who suffer from type 2 diabetes mellitus. According to a report issued last year by the Centers for Disease Control and Prevention, >10% of Americans have type 2 diabetes mellitus; thus, this relationship may have a major impact on dental health. However, no researchers had studied this patient group using a sufficiently large U.S. population and controlling for possible confounding variables.
Recently, Yip et al from the University of North Carolina at Chapel Hill published a case-controlled study of >15,000 patients to determine (1) whether apical periodontitis is independently associated with type 2 diabetes mellitus after controlling for confounding variables and (2) whether varying levels of glycated hemoglobin (HbA1c) were associated with apical periodontitis. From the records of 7 dental clinics at hospitals spread throughout North Carolina, the researchers identified 7749 patients with diagnoses of both apical periodontitis and type 2 diabetes mellitus. They then created a control group of the same number of patients from the same hospital clinics, matched by age, race and sex, who did not have a diagnosis of apical periodontitis.
In addition to periodontal and diabetes status, the following variables for each patient were recorded:
- oral cellulitis
- body mass index (categorized as obese or nonobese)
- primary and secondary hypertension
- chronic kidney disease
- smoking status
- use of metformin (a drug commonly prescribed to treat type 2 diabetes mellitus)
- use of statins (a class of drugs commonly prescribed for hypercholesterolemia)
Several regression models were created to determine whether an association exists between periodontal disease and type 2 diabetes mellitus, and what (if any) impact any of the studied variables had on that association.
Nearly twice as many patients with apical periodontitis also had a diagnosis of type 2 diabetes mellitus. This relationship held even after controlling for demographic factors and potential confounding variables. Interestingly, patients taking either statins or metformin had significantly lower odds of developing apical periodontitis (Table 1). Patients with poorly controlled HbA1c levels (defined as HbA1c >8.0) had significantly greater odds of developing apical periodontitis, as did current and former smokers and patients diagnosed with atherosclerosis or hypertension.
While it is impossible for a study like this to establish a direct cause-and-effect relationship between type 2 diabetes mellitus and apical periodontitis, this study’s large sample size and strict control of potential confounding variables allowed it to show a strong independent association between the 2 conditions, with higher HbA1c levels significantly associated with apical periodontitis. Patients on metformin therapy, which is frequently prescribed to control HbA1c, were less likely to be afflicted with apical periodontitis.
Yip N, Liu C, Wu D, Fouad AF. The association of apical periodontitis and type 2 diabetes mellitus: a large hospital network cross-sectional case–controlled study. J Am Dent Assoc 2021; 152:434-443.