Relationship between periodontal disease and C-reactive protein among adults in the atherosclerosis risk in communities study

Background: Moderately elevated serum C-reactive protein (CRP) concentration is a systemic marker of inflammation and a documented risk factor for cardiovascular disease in otherwise healthy persons. Unrecognized infections, such as periodontal disease, may induce an acute-phase response, elevating CRP levels. We evaluated the association between periodontal disease and CRP levels in adults in the Atherosclerosis Risk in Communities study. Methods: Oral examinations were conducted between January 1, 1996, and December 31, 1998, on 5552 ARIC participants (aged 52-74 years) from 4 US communities. Periodontal disease was quantified as the percentage of periodontal sites with pocket depth of 4 mm or more. Serum CRP concentration was quantified in milligrams per liter using an enzyme-linked immunosorbent assay. Results: Mean (SE) CRP level was 7.6 (0.6) mg/L among people with extensive periodontal pockets (>30% of sites with pocket depth greater than or equal to4 mm), approximately one-third greater than that for people with less extensive periodontal pockets (5.7 [0.1] mg/L). In a multivariable linear regression model that controlled for age, sex, diabetes mellitus, cigarette use, and nonsteroidal anti-inflammatory drug use, the association of extensive periodontal pockets with CRP concentration was modified by body mass index (BMI; calculated as weight in kilograms divided by the square of height in meters). For people with a BMI of 20, the model predicted a 2-fold difference in mean CRP concentration between periodontal pocket groups (7.5 vs 3.6 mg/L), but the difference decreased with increasing BMI and was negligible when BMI equaled 35. Conclusions: Extensive periodontal disease and BMI are jointly associated with increased CRP levels in otherwise healthy, middle-aged adults, suggesting the need for medical and dental diagnoses when evaluating sources of acute-phase response in some patients.