Background: Several epidemiological studies have demonstrated an association between periodontal disease and coronary heart disease (CHD). The association could be a result of confounding by mutual risk factors. The present study was undertaken in a Danish population to reveal the significance of common risk factors.

Methods: The investigation was conducted as a case-control study comprising 250 individuals: 110 individuals with verified CHD from a Department of Cardiovascular Medicine and 140 control individuals without CHD from the Copenhagen City Heart Study. Information on diabetic status, smoking habits, alcohol consumption, physical activity, school attendance, household income, body weight and height, triglyceride, and serum cholesterol was obtained. Full-mouth probing depth (PD), clinical attachment loss (CAL), bleeding on probing (BOP), and alveolar bone level (ABL) on radiographs were registered. ABL was stratified into ABL1 = ABL ≤2 mm; ABL2 = ABL >2 to ≤4 mm; and ABL3 = ABL >4 mm. Multiple logistic regression models with stepwise backward elimination were used allowing variables with P <0.15 to enter the multivariate analysis.

Results: The CHD group had a significantly lower outcome with respect to PD, BOP, CAL, and ABL. For participants <60 years old, only risk factors such as smoking and diabetic status entered the multivariate analysis. For the ABL3 group, there was a significant association with CHD for participants <60 years old, the odds ratio being 6.6 (1.69 to 25.6). For participants ≥60 years old, there was no association.

Conclusions: The present study showed a positive association between periodontal disease and CHD in agreement with several other studies. The association was highly age dependent and could only be attributed to diabetes and smoking to some extent.