The use of different measurements and definitions of periodontal disease in the study of the association between periodontal disease and risk of myocardial infarction

Background: The role of periodontal disease as an independent risk factor for cardiovascular disease (CVD) has been under debate because of the inconsistency of findings across studies. One of the major issues is the method used to assess or define periodontal disease. The present study assesses if the observed association between periodontal disease and incident myocardial infarction (MI) depends on the measurements and/ or criteria used to define periodontal disease. Methods: A population-based case-control study to evaluate the association between PD and risk of MI was conducted between 1997 and 2001 in Western New York with 537 cases and 800 controls, aged 35 to 69 years. Cases were survivors of incident MI from local hospitals in Erie and Niagara counties. Controls were randomly selected from residents of the same counties. Periodontal disease was assessed using interproximal clinical attachment loss (CAL), probing depth (PD), alveolar crest height (ACH), and number of missing teeth. From these measurements, four different case definitions of periodontal disease were created. Results: Using the continuous forms of periodontal measurements, the odds ratios (ORs) (95% confidence interval) of the association with incident MI were 1.46 (1.26 to 1.69), 2.19 (1.66 to 2.89), 1.30 (1.14 to 1.49), and 1.04 (1.02 to 1.07) for mean CAL, PD, ACH, and number of missing teeth, respectively. Regardless of the case definition of periodontal disease, the estimates of the association with incident MI were statistically significant. Conclusions: The observed association between periodontal disease and incident MI was consistent across different measurements and/or case definitions of periodontal disease used. The magnitude of the association varies depending on the mepsurements or the criteria used to define periodontal disease.