Michael P Rethman DDS MS
Periodontitis in adults is a risk factor for coronary heart disease (CHD) independent of traditional Framingham risk factors, including socioeconomic status.
A review considering the best available evidence found chronic periodontitis to be an independent risk factor or marker for CHD-caused maladies such as myocardial infarction. However, it is unclear if preventing or successfully treating periodontitis lowers the risk of developing CHD.
Is chronic periodontitis an independent risk factor (or marker) for subsequent CHD events (morbidity or mortality) in adults with no prior histories of CHD?
A comprehensive search of MEDLINE for studies from 1966 through March 2008 identified 148 titles. Of those studies, 68 of them were selected based on abstract reviews. Seven studies met inclusion criteria: 1) prospective cohort design, plus; 2) CHD assessed as an outcome, plus; 3) published in English. Meta-analyses were performed and Forest plots developed.
The authors analyzed cohort studies whose number of participants ranged between 175 and 170,000 and which reported 5 to 21 year-follow-up periods. Subjects were self-identified or identified by exam for the presence of various signs (e.g. bone loss, tooth loss, etc.) indicative of periodontitis. A higher risk of CHD was noted when signs of chronic periodontitis (relative risk [RR]=1.24, 95% confidence interval [CI]=1.01-1.51) were noted. The risk of CHD-related morbidity or mortality also was greater in those subjects with 10 or fewer natural teeth (RR=1.34; CI=1.10-1.63). Meta-analysis of 2 large, long-term studies that related gingivitis to CHD revealed a statistically insignificant correlation. Significant heterogeneity between studies was detected, but tests for publication bias were negative. Subgroup analyses of those studies in which Framingham risk factors were reported suggested that periodontitis is an independent risk-factor for adverse CHD-related outcomes.
Meta-analyses of 7 prospective cohort studies revealed that periodontitis and/or the presence of 0 to 10 teeth (suggestive of past periodontitis) coincide with an increased (24-35%) risk of CHD-related maladies. This relationship appears independent of known environmental confounders such as smoking.
Source of Funding:
Agency for Healthcare Research and Quality (USA)
Importance and Context:
Chronic periodontitis is a common disease that may be associated with CHD (or other serious systemic maladies such as stroke). As a result, dentists should be made aware of this relationship as well as inform their patients about it.
Strengths and Weaknesses of the Systematic Review:
Acceptable methods were used to identify the best available evidence published in English-language journals. The requirement for prospective cohort studies strengthens the applicability of this review’s conclusions. Meta-analyses and Forest plots helped convey results. However, the authors also included studies that measured non-CHD, cardiovascular conditions (such as stroke) as outcomes, detracting from the purpose for a review ostensibly focused on CHD. This tactic probably resulted in small but clinically inconsequential overstatements of the RR’s they reported. Furthermore, the authors failed to use the most current dental terminology. For example, the term "chronic periodontitis” is preferred by periodontal experts instead of the authors’ use of "adult-type of the periodontal diseases."
Strengths and Weaknesses of the Evidence:
The statistical power was substantial since the evidence was drawn from prospective cohort studies, some of which had many thousands of subjects and/or were of long duration. Additionally, because these prospective studies drew samples from the general population, generalizations can be made about the relative risks of contracting CHD. However, it remains unclear if the relationship between chronic periodontitis and CHD is one of cause-and-effect. Instead, perhaps some individuals are more prone to both chronic periodontitis and CHD. Prospective, randomized controlled intervention trials would be valuable to determine if preventing or treating chronic peridontitis correlates with a decreased incidence of CHD.
Implications for Dental Practice:
Patients should be advised that studies have shown an association between periodontitis and CHD. However, patients also should be informed that, despite plausible explanations regarding how a long-term infection like chronic periodontitis may contribute to CHD in some individuals, it remains unclear if actual cause-and-effect relationships exist. Whether or not future research establishes cause-and-effect oro-systemic links, patients may be advised that they should strive for optimal oral health.