Age-dependent associations between chronic periodontitis/edentulism and risk of coronary heart disease

Abstract

Background: Several epidemiological studies have suggested periodontitis as a risk factor for coronary heart disease (CHD), but results have been inconsistent.

Methods and results: We evaluated the association between clinical and radiographic measures of periodontitis, edentulism, and incident CHD (angina, myocardial infarction, or fatal CHD) among 1203 men in the VA Normative Aging and Dental Longitudinal Studies who were followed up with triennial comprehensive medical and dental examinations up to 35 years (median 24 years). Cox proportional hazards models with time-varying effects of exposure and potential confounders were fit. We found a significant dose-dependent association between periodontitis and CHD incidence among men < 60 years of age (hazard ratio 2.12, 95% confidence interval 1.26 to 3.60 comparing highest versus lowest category of radiographic bone loss, P for trend=0.02), independent of age, body mass index, smoking, alcohol intake, diabetes mellitus, fasting glucose, total cholesterol, high-density lipoprotein cholesterol, triglycerides, hypertension, systolic and diastolic blood pressure, education, marital status, income, and occupation. No association was found among men > 60 years of age. Similar results were found when the sum of probing pocket depths was used as a measure of periodontitis. Among men > or = 60 years of age, edentulous men tended to have a higher risk of CHD than dentate men in the lowest bone loss (hazard ratio 1.61, 95% confidence interval 0.95 to 2.73) and lowest pocket depth (hazard ratio 1.72, 95% confidence interval 1.03 to 2.85) categories, independent of confounders.

Conclusions: Chronic periodontitis is associated with incidence of CHD among younger men, independent of established cardiovascular risk factors.

Fig. 1

Hazard Ratio (HR) and 95% confidence interval (CI) per one unit increase in mean bone loss score (20% bone loss) as a function of age

Fig. 2. Possible pathways explaining the periodontitis/CHD association (modified after Beck et al. and Danesh et al. 12)

The dotted arrows describe the causal association of interest, as chronic periodontitis may be a cause of cardiovascular disease through direct (bacteremia) and indirect (systemic inflammation) effects . Oral bacteria are considered a necessary cause of chronic periodontitis (pathway 1) . Smoking is a strong environmental risk factor for chronic periodontitis (2) and is also an important risk factor for cardiovascular disease (4), which may in part be mediated through its effect on systemic inflammation (3), e.g. elevated CRP concentrations . Common susceptibility to the inflammatory diseases, including periodontitis and cardiovascular disease (7,8,9), is determined by genetic (5) and environmental factors, some of which may also be established cardiovascular risk factors (6). There is compelling evidence for a strong genetic base for both periodontitis as well as cardiovascular disease , some of which is likely mediated through inflammatory mechanisms (5). On the other hand, diabetes is an established cardiovascular risk factor that may increase the susceptibility to both periodontitis and cardiovascular disease through the increased formation of advanced glycolysation end products, which are pro-inflammatory (6) . Note that even perfect adjustment for established cardiovascular risk factors such as smoking and diabetes, a pro-inflammatory phenotype (at least as far as determined by genetic factors) that predisposes to both periodontitis and CHD may confound the periodontitis/CHD association (non-causal pathway).