The following literature review will explore research that has investigated the relationship between dental health and cardiovascular disease. The discussion will focus on the significance of the association between oral health and cardiovascular disease, oral health and mortality due to cardiovascular disease, as well as other potential risk factors associated with this relationship.
An effective starting point in the investigation of the association between dental health and cardiovascular disease is to compare oral health of individuals with and without heart disease. Starkhammar et al., (2008) sought to examine the periodontal conditions of individuals with coronary heart disease and those without any heart problems. The authors recognized the severity of coronary heart disease, and how a key component to this disease is inflammation. Prior research indicated that oral diseases resulting in inflammation may play a significantly contributing role to the development of coronary heart disease (Starkhammar et al., 2008). Therefore, the authors sought to use coronary angiography to compare periodontal conditions of individuals with and without coronary heart disease. The test group (those with coronary heart disease) totaled 161, while the control group numbered 162.
Various clinical parameters were used in the study in order to assess periodontal conditions. The parameters included number of teeth remaining subjects, the presence or absence of visible plaque on the teeth and gums, The distance between the gingival margin and the bottom of the probed pocket (PPD), as well as the presence or absence of bleeding after the bottom of the pocket is probed (BOP). Other information used to assess periodontal conditions included full-mouth intra-oral radiographs and measurements of alveolar bone level (Starkhammar et al., 2008). Based on the results yielded from these assessments, the subjects were then grouped accordingly into five separate groups based on type and severity of periodontal conditions.
In order to statistically compare the test and control groups in the study, the Mann-Whitney test was employed. Furthermore, a logistical regression analysis was performed to assess the differences in the predictor variable presented by the test and control groups, with p = 0.05 set as the statistical significance level (Starkhammar et al., 2008). Overall, results indicated that the group with coronary heart disease presented with significantly more symptoms of periodontal disease, including reduced mean bone level, less natural teeth, greater numbers of periodontal pockets, and more bleeding upon probing (Starkhammar et al., 2008). Furthermore, the authors determined that individuals with categorized in the two groups presenting with the most severe periodontal conditions showed an odds ratio of 5.74 for having coronary heart disease after age and smoking variables were controlled for (Starkhammar et al., 2008).
Based on the results of this study, the authors concluded that periodontal disease was indeed more prevalent among individuals with coronary heart disease than among individuals without heart disease (Starkhammar et al., 2008). The authors noted that the findings of this study were consistent with the results of other studies linking periodontal disease to coronary heart disease. It is also recognized that future research is required to determine whether treatment of periodontal disease is an effective means in decreasing risk or even preventing coronary heart disease (Starkhammar et al., 2008).
Similar results were presented in a study conducted by Dietrich et al. (2008), which demonstrated that chronic periodontal disease is significantly associated with coronary heart disease among a sample of younger men. The relationship found in this study existed independent of any other usual risk factors for cardiovascular disease. The scale of this study was quite large in scope, as 1203 men were examined. Specifically, the study determined a significant dose-dependent relationship between periodontal disease and coronary heart disease in men under the age of 60 years, independent of smoking, body mass index, alcohol consumption, age, education, blood pressure, income, marital status, and occupation (Dietrich et al., 2008).
The association between periodontal disease and cardiovascular disease was taken a step further by Ide et al. (2008), who examined the extent to which oral health symptoms could significantly predict mortality from cardiovascular disease. This large-scale study examined 4,139 individuals between the ages of 40 to 79 years old with regards to oral symptoms through a survey that questioned participants about whether they had symptoms of oral disease such as less sensitive teeth, difficulty chewing, or a sticky feeling mouth. After adjusting for factors such as socio-economic status, lifestyle, and disease history, the authors estimated hazard ratios and 95% confidence intervals for mortality. Results of the study indicated that some oral symptoms of periodontal disease may be significant predictors of death due to cardiovascular disease (Ide et al., 2007).
Similarly, a study performed by Holmlund et al. (2010) investigated the factors involved in the relationship between oral health and cardiovascular disorder with an emphasis on whether number of teeth could be used as a significant predictor of mortality due to cardiovascular disease. This was a large scale study that used dental and periodontal examination information from 7,674 individuals between 1976 and 2002. The subjects in the study were 3,300 males and 4,374 females that ranged in age from 20 to 89 years old.
Cause of death of the subjects was examined in relation to a number of factors, including number of teeth remaining, number of deepened periodontal pockets, severity of periodontitis, and bleeding upon probing (Holmlund et al., 2010). 629 subjects died during a 12-year follow-up period, and cause of death for 299 of these individuals was cardiovascular disease. The authors adjusted for age, gender, and smoking, and it was found that number of remaining teeth was the only factor that could significantly predict mortality due to cardiovascular disease (Holmlund et al., 2010). The other factors, including number of deepened periodontal pockets, bleeding upon probing, and severity of periodontal disease were not determined to be significantly related to mortality. Furthermore a Cox regression analysis was used to determine that subjects with less than 10 teeth were seven times more likely to die from coronary heart disease in comparison to subjects with more than 25 teeth (Holmlund et al., 2010).
Unlike many other studies linking severity of periodontal disease to mortality due to cardiovascular disease, the study by Holmlund et al. (2010) did not find a similar correlation. It was noted by the authors that there is no standard definition for periodontal disease, which makes it difficult to compare different studies investigating the link between oral health and cardiovascular disease (Holmlund et al., 2010). This large-scale study found strength in its large number of subjects and long follow-up period, but the study was limited in that all of the subjects were white, so whether the results yielded could be generalized to other ethnic groups was unknown (Holmlund et al., 2010).
The association between periodontal disease and cardiovascular disease has been well established through several research studies. However, this association may not be directly causal, and may instead be confounded by risk factors that are mutual to each condition. This was possibility was investigated by Geismar et al. (2006), who examined the significance of common risk factors of periodontal disease and cardiovascular disease. This study consisted of a total of 250 participants, 110 of which had verified coronary heart disease and 140 did not have coronary heart disease. Several factors were assessed for all participants including smoking habits, diabetic status, physical activity, levels of alcohol consumption, household income, school attendance, height and body weight, serum cholesterol, and triglycerides (Geismar et al., 2006). Also, periodontal conditions were assessed through the examination of full-mouth probing depth, bleeding on probing, clinical attachment loss, and alveolar bone level. A multivariate analysis was conducted that only included variables with p < 0.15, determined through multiple logistic regression models with stepwise backward elimination (Geismar et al., 2006).
Results of this study demonstrated a significant association between severity of periodontal disease and coronary heart disease for individuals over the age of 60 years old (Geismar et al., 2006). This association was not found for participants under the age of 60 years, and the only confounding risk factors that entered the multivariate analysis for this younger age group were diabetic status and smoking. Furthermore, the results of this study are in agreement with the findings of Starkhammar et al. (2008), demonstrating a significant, positive relationship between periodontal disease and coronary heart disease (Geismar et al., 2006). It is observed by Geismar et al. (2006) that there are risk factors common to both periodontal disease and coronary heart disease, with a large proportion of the association between periodontal disease and coronary heart disease attributable to smoking and diabetic status. It was also noted by the authors that a possible biological explanation exists for the association between periodontal disease and cardiovascular disease involving chronic infections and inflammatory processes, and other risk factors such as smoking and diabetes could be related to these factors as well (Geismar et al., 2006).
Genetic predisposition as a potential confounding factor for periodontal disease and cardiovascular disease was controlled for in a study conducted by Tabrizi et al. (2007). This study…