Periodontitis and cardiovascular disease: periodontal treatment lowers plasma cholesterol.

In this issue of the Southern Medical Journal, Dr. Oz and colleagues report on the beneficial effect of periodontal treatment in hypercholesterolemic patients suffering from periodontitis. Periodontitis is an infectious disease caused by a small group of predominantly anaerobic Gram negative bacteria present on the tooth surface as microbial biofilms. Lipopolysaccharides and other microbial substances gain access to the gingival tissue and initiate and perpetuate an inflammatory reaction, which leads to the destruction of the periodontal ligament and alveolar bone and, finally, to tooth loss. Numerous case control and cohort studies have indicated that patients with periodontitis have an increased risk of cardiovascular disease (CVD), ie, myocardial infarction, stroke and peripheral arterial disease, when compared with subjects with a healthy periodontium. The association between periodontitis and CVD may be because of common risk factors such as smoking, diabetes mellitus, aging, male gender and socioeconomic factors, but there is also good evidence of periodontitis being an independent risk factor of CVD. Periodontitis is believed to cause a low, but long-lasting, systemic inflammatory reaction, which in turn contributes to the development of atherosclerosis. Furthermore, periodontal pathogens have been identified in early as well as advanced atherosclerotic lesions. There is also some evidence that periodontitis is associated with increased plasma concentrations of pro-atherogenic lipoproteins, in particular, cholesterol-rich low-density lipoproteins (LDL) and triglycerides. Although numerous prospective studies with thousands of patients have shown the association between periodontitis and cardiovascular disease, no studies have been done so far demonstrating that treatment of periodontitis decreases the risk of CVD as measured by the frequency of hard endpoints such as death or hospitalization due to myocardial infarction or stroke. Due to the large number of patients to be enrolled, the long follow-up periods, and the ethical problems that would arise from a control group of periodontitis patients without appropriate treatment, such studies will probably not be done in the future. However, short-term studies monitoring surrogate markers of CVD, ie, biochemical risk factors, have appeared to be very helpful in obtaining further evidence for periodontitis as an independent CVD risk factor. In these studies, established risk factors of CVD, such as increased plasma levels of C-reactive protein, fibrinogen, pro-inflammatory cytokines or other acute-phase reactants, were measured before and after (up to 6 months) local therapy of periodontitis. Some, but not all, of these studies have shown that the periodontal treatment significantly decreases plasma concentrations of the biochemical CVD risk markers. Hypercholesterolemia was the first biochemical risk factor of atherosclerosis and is still considered one of its most important risk factors. Hypercholesterolemia is frequently found in patients with moderate and severe periodontitis. Dr. Oz and colleagues demonstrate that periodontal treatment can reduce cholesterol level. Fifty subjects (mean age 50 7 yr) with more than 3 dental pockets with a probing depth 4 mm were included in this study. Three months after therapy, the authors not only observed a significant reduction in the clinical signs of local inflammation and periodontal destruction, but they also measured a significant reduction of total cholesterol by about 12% (from 245 21–214 33 mg/dL) and a reduction of LDL cholesterol by 25% (from 155 19–116 37 mg/dL). If there are no other risk factors, an LDL cholesterol level of 155 mg/dL is considered to be within the tolerable limits. Nevertheless, a reduction by 25% would result in a substantial reduction in the risk for myocardial infarction within 10 years. Dependent on age, gender and the prevalence of further risk factors (smoking, previous cardiovascular event, family history of CVD, etc.), a statistical risk reduction by 30 to 50% could be expected. Recently, another study demonstrating a significant reduction of mean LDL cholesterol level in 40 patients (from 132 23–116 19 mg/dL) six months after periodontal therapy was published by D’Aiuto et al. In an earlier study on 32 periodontitis patients with comparatively low basal LDL cholesterol levels (median 121 mg/dL), we did not see a significant reduction when the measurements were repeated 3 months after therapy (median 114 mg/dL). The results of the three studies taken together appear to reveal that the effect of periodontal therapy on LDL cholesterol level seems to be more obvious at higher basal levels, compared with lower basal levels. A simple and practical conclusion that can be drawn from the studies, providing evidence that periodontitis may be an independent risk factor of CVD and that periodontal From the Department of Anesthesiology and Intensive Care Medicine, Experimental Anesthesiology and Hemostasis, University Hospital Jena, Jena, Germany.