Systemic effects of periodontitis: Epidemiology of periodontal disease and cardiovascular disease

There have been 42 published studies describing associations between oral conditions and cardiovascular diseases. In the absence of randomized controlled trials, the 16 longitudinal studies represent the highest level of evidence available. However, two databases produced eight of the 16 studies. There also is extensive variability in definitions of the oral exposure that include salivary flow, reported periodontal disease, number of teeth, oral organisms, antibodies to oral organisms, Total Dental index, Community Periodontal Index of Treatment Needs, plaque scores, probing depth, attachment loss, and bone level. Variability also exists in the cardiovascular outcomes that include atherosclerosis measures and events, such as hospitalization for coronary heart disease (CHD), chronic CHD, fatal CHD, total stroke, ischemic stroke, and revascularization procedures. One of the criticisms of this research is that the exposure has not been represented by measures of infection. To begin to address this concern, we present new data showing that patterns of high and low levels of eight periodontal pathogens and antibody levels against those organisms are related to clinical periodontal disease as well as other characteristics of the individuals, such as age, race, gender, diabetic status, atherosclerosis, and CHD. As others before us, we conclude that the cumulative evidence presented above supports, but does not prove, a causal association between periodontal infection and atherosclerotic cardiovascular disease or its sequelae. A number of legitimate concerns have arisen about the nature of the relationship and, indeed, the appropriate definitions for periodontal disease when it is thought to be an exposure for systemic diseases. There is still much work needed to identify which aspects of the exposure are related to which aspects of the outcome. Principal component analyses illustrate the complexity of the interactions among risk factors, exposures, and outcomes. These analyses provide an initial clustering that describes and suggests the presence of specific syndromes.