Table of Contents
- 1 Is there a link between periodontal disease, coronary artery disease and stroke?
Scientific studies have shown that there is a link between the presence of severe periodontal disease and the presence of cardiovascular disease and stroke. This association is especially apparent in the occurrence of stroke (cerebral vascular accident–CVA). It is not clear, however, that there is a causal relationship between periodontal disease and Coronary Artery Disease or Cerebrovascular disease. A correlation between two processes does not necessarily imply that one causes the other.
The correlation could be caused by overlying factors that influence both processes separately. These factors appear to be environmental and genetic factors, as well as acquired risk factors such as smoking, mental anxiety, depression, obesity, diabetes mellitus and exposure to tobacco.
The evidence for a direct causal relationship between periodontal disease and cardiovascular disease
Bacteria from the mouth is known to enter the bloodstream through the gums. These same bacteria have been found clumped in athrosclerotic (artery) plaques. One theory is that these bacteria stick to the fatty plaques in the bloodstream, directly contributing to arterial blockages. Another theory suggests that the bacteria, upon entering the bloodstream, stimulate an immune response involving C-reactive protein which then stimulates the thickening of the walls of arteries. No studies to date have confirmed either of these theories.
A 2005 study of 657 people without known heart disease, done by epidemiologist Moise Desvarieux, found that people who had higher blood levels of certain disease-causing bacteria in the mouth were more likely to have atherosclerosis in the carotid artery in the neck. The conclusion of the study was that there is a direct relationship between the presence of periodontal disease and a subclinical sign of athrosclerosis (thickening of the walls of the carotid artery). The study does not address a causal link between the bacteria and atherosclerotic plaques.
The evidence against a direct causal relationship between periodontal disease and cardiovascular disease
A major study involving over 4,000 patients and 17 years of follow up showed no evidence of a decreased risk of coronary heart disease or stroke if chronic periodontitis was eliminated. (The study was from the July 2001 issue of The Journal of the American Dental Association. The lead author was P.P. Hujoel, PhD, assoc. prof, school of dentistry, Univ. of Washington, Seattle.) In other words, there is still no evidence that either disease is involved in causing the other. On the other hand, although past studies have not supported a causal relationship between periodontitis and cardio/cerebral artery disease, other studies have concluded that periodontal disease is a risk factor, or marker independent of traditional CAD risk factors, with relative risk estimates ranging from 1.24 to 1.35. In other words, persons with severe periodontal disease are between 24% and 35% more likely also to have coronary artery disease. This means that the presence of severe periodontal bony destruction may serve as a marker for persons who are also more susceptible to vascular diseases.
A more recent study (2004) by Moïse Desvarieux, MD, PhD has found that there is a direct link between the bacteria involved in periodontal disease and the progression of atheroscleroses. Their data provided evidence of a direct relationship between periodontal microbiology and subclinical atherosclerosis. They found that this relationship exists independent of C-reactive protein. Note that this evidence does not contradict the evidence presented in the earlier study linked in the previous paragraph. While there appears to be a direct link between the presence of periodontal disease and the progression of atherosclerosis, this does not necessarily imply that there is a correlation with an increased risk of coronary heart disease or stroke.
For more on the relationship between CHD and plaque, please see the following articles:
A blood test which measures the level of C-reactive protein (CRP) is a sensitive marker of inflammation. CRP levels can help to identify those patients whose immune system responds most actively to stimuli. The amount of inflammation caused by an ischemic stroke is measurable by determination of CRP concentrations. Furthermore, the level of CRP helps to predict outcome of CVA (i.e. how severe the cerebral damage will be). Periodontal disease, cardio vascular disease and cerebral artery disease are all characterized by inflammation, and all are associated with high levels of CRP.
For much more on the relationship of periodontal disease to systemic immune functions please see The American Journal of Cardiology and Journal of Periodontology Editors’ Consensus: Periodontitis and Atherosclerotic Cardiovascular Disease.
Diabetes is a disease that interferes with the metabolism of glucose. Glucose is the sugar that all other forms of sugar are converted to before entering the bloodstream. The term “metabolism” involves the way that glucose is utilized in all the individual cells throughout the body. Since glucose is the essential fuel that makes all other cellular functions possible. Anything that interferes with its utilization can cause those cells to malfunction. This includes all the cellular components that compose the periodontal tissues.
Persons with uncontrolled, or poorly controlled diabetes are much more prone to rapid bone loss resulting from periodontal disease. On the other hand, the presence of periodontal disease depends strictly on the persistent presence of dental plaque on and around the teeth at the periodontal attachment. In other words, good oral hygiene will always prevent the disease, regardless of the presence or absence of diabetes or other metabolic diseases. Thus, diabetes does not CAUSE gum disease. It can, however, accelerate the destruction of bone in the presence of poor oral hygiene. Good oral hygiene (including good interproximal–between the teeth–hygiene) will prevent periodontal disease even in the presence of uncontrolled diabetes. Poor oral hygiene, in the presence of uncontrolled diabetes is a prescription for the loss of a person’s teeth.
Finally, there is no known linkage in the other direction. The presence of periodontal disease does NOT necessarily infer that a patient also has diabetes.